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提交 d7393144 编写于 作者: J jrose
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7012650: implement JSR 292 EG adjustments through January 2010 

Summary: misc. EG changes and polishes (excluding 7013417)
Reviewed-by: twisti
上级 f39741d7
隐藏空白更改
内联 并排
Showing with 1656 addition and 746 deletion
jdk/src/share/classes/java/dyn/CallSite.java
浏览文件 @ d7393144
/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2008, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
......@@ -78,7 +78,7 @@ static {
}
private static CallSite bootstrapDynamic(MethodHandles.Lookup caller, String name, MethodType type) {
// ignore caller and name, but match the type:
return new ConstantCallSite(MethodHandles.collectArguments(printArgs, type));
return new ConstantCallSite(printArgs.asType(type));
}
</pre></blockquote>
* @author John Rose, JSR 292 EG
......@@ -86,6 +86,7 @@ private static CallSite bootstrapDynamic(MethodHandles.Lookup caller, String nam
abstract
public class CallSite {
private static final Access IMPL_TOKEN = Access.getToken();
static { MethodHandleImpl.initStatics(); }
// Fields used only by the JVM. Do not use or change.
private MemberName vmmethod; // supplied by the JVM (ref. to calling method)
......@@ -125,8 +126,8 @@ public class CallSite {
}
/**
* Report the type of this call site's target.
* Although targets may change, the call site's type can never change.
* Returns the type of this call site's target.
* Although targets may change, any call site's type is permanent, and can never change to an unequal type.
* The {@code setTarget} method enforces this invariant by refusing any new target that does
* not have the previous target's type.
* @return the type of the current target, which is also the type of any future target
......@@ -154,73 +155,40 @@ public class CallSite {
}
/**
* Report the current linkage state of the call site, a value which may change over time.
* <p>
* If a {@code CallSite} object is returned
* from the bootstrap method of the {@code invokedynamic} instruction,
* the {@code CallSite} is permanently bound to that instruction.
* When the {@code invokedynamic} instruction is executed, the target method
* of its associated call site object is invoked directly.
* It is as if the instruction calls {@code getTarget} and then
* calls {@link MethodHandle#invokeExact invokeExact} on the result.
* <p>
* Unless specified differently by a subclass,
* the interactions of {@code getTarget} with memory are the same
* as of a read from an ordinary variable, such as an array element or a
* non-volatile, non-final field.
* <p>
* In particular, the current thread may choose to reuse the result
* of a previous read of the target from memory, and may fail to see
* a recent update to the target by another thread.
* <p>
* In a {@linkplain ConstantCallSite constant call site}, the {@code getTarget} method behaves
* like a read from a {@code final} field of the {@code CallSite}.
* <p>
* In a {@linkplain VolatileCallSite volatile call site}, the {@code getTarget} method behaves
* like a read from a {@code volatile} field of the {@code CallSite}.
* <p>
* This method may not be overridden by application code.
* Returns the target method of the call site, according to the
* behavior defined by this call site's specific class.
* The immediate subclasses of {@code CallSite} document the
* class-specific behaviors of this method.
*
* @return the current linkage state of the call site, its target method handle
* @see ConstantCallSite
* @see VolatileCallSite
* @see #setTarget
* @see ConstantCallSite#getTarget
* @see MutableCallSite#getTarget
* @see VolatileCallSite#getTarget
*/
public final MethodHandle getTarget() {
return getTarget0();
}
/**
* Privileged implementations can override this to force final or volatile semantics on getTarget.
*/
/*package-private*/
MethodHandle getTarget0() {
return target;
}
public abstract MethodHandle getTarget();
/**
* Set the target method of this call site.
* Updates the target method of this call site, according to the
* behavior defined by this call site's specific class.
* The immediate subclasses of {@code CallSite} document the
* class-specific behaviors of this method.
* <p>
* Unless a subclass of CallSite documents otherwise,
* the interactions of {@code setTarget} with memory are the same
* as of a write to an ordinary variable, such as an array element or a
* non-volatile, non-final field.
* <p>
* In particular, unrelated threads may fail to see the updated target
* until they perform a read from memory.
* Stronger guarantees can be created by putting appropriate operations
* into the bootstrap method and/or the target methods used
* at any given call site.
* The type of the new target must be {@linkplain MethodType#equals equal to}
* the type of the old target.
*
* @param newTarget the new target
* @throws NullPointerException if the proposed new target is null
* @throws WrongMethodTypeException if the proposed new target
* has a method type that differs from the previous target
* @throws UnsupportedOperationException if the call site is
* in fact a {@link ConstantCallSite}
* @see CallSite#getTarget
* @see ConstantCallSite#setTarget
* @see MutableCallSite#setTarget
* @see VolatileCallSite#setTarget
*/
public void setTarget(MethodHandle newTarget) {
checkTargetChange(this.target, newTarget);
setTargetNormal(newTarget);
}
public abstract void setTarget(MethodHandle newTarget);
void checkTargetChange(MethodHandle oldTarget, MethodHandle newTarget) {
MethodType oldType = oldTarget.type();
......@@ -236,25 +204,25 @@ public class CallSite {
/**
* Produce a method handle equivalent to an invokedynamic instruction
* which has been linked to this call site.
* <p>If this call site is a {@linkplain ConstantCallSite constant call site},
* this method simply returns the call site's target, since that will never change.
* <p>Otherwise, this method is equivalent to the following code:
* <p><blockquote><pre>
* <p>
* This method is equivalent to the following code:
* <blockquote><pre>
* MethodHandle getTarget, invoker, result;
* getTarget = MethodHandles.lookup().bind(this, "getTarget", MethodType.methodType(MethodHandle.class));
* getTarget = MethodHandles.publicLookup().bind(this, "getTarget", MethodType.methodType(MethodHandle.class));
* invoker = MethodHandles.exactInvoker(this.type());
* result = MethodHandles.foldArguments(invoker, getTarget)
* </pre></blockquote>
*
* @return a method handle which always invokes this call site's current target
*/
public final MethodHandle dynamicInvoker() {
if (this instanceof ConstantCallSite) {
return getTarget0(); // will not change dynamically
}
public abstract MethodHandle dynamicInvoker();
/*non-public*/ MethodHandle makeDynamicInvoker() {
MethodHandle getTarget = MethodHandleImpl.bindReceiver(IMPL_TOKEN, GET_TARGET, this);
MethodHandle invoker = MethodHandles.exactInvoker(this.type());
return MethodHandles.foldArguments(invoker, getTarget);
}
private static final MethodHandle GET_TARGET;
static {
try {
......
jdk/src/share/classes/java/dyn/ClassValue.java
浏览文件 @ d7393144
/*
* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
......@@ -31,10 +31,14 @@ import java.util.concurrent.atomic.AtomicReference;
import java.lang.reflect.UndeclaredThrowableException;
/**
* Lazily associate a computed value with (potentially) every class.
* Lazily associate a computed value with (potentially) every type.
* For example, if a dynamic language needs to construct a message dispatch
* table for each class encountered at a message send call site,
* it can use a {@code ClassValue} to cache information needed to
* perform the message send quickly, for each class encountered.
* @author John Rose, JSR 292 EG
*/
public class ClassValue<T> {
public abstract class ClassValue<T> {
/**
* Compute the given class's derived value for this {@code ClassValue}.
* <p>
......@@ -45,61 +49,41 @@ public class ClassValue<T> {
* but it may be invoked again if there has been a call to
* {@link #remove remove}.
* <p>
* If there is no override from a subclass, this method returns
* the result of applying the {@code ClassValue}'s {@code computeValue}
* method handle, which was supplied at construction time.
* If this method throws an exception, the corresponding call to {@code get}
* will terminate abnormally with that exception, and no class value will be recorded.
*
* @param type the type whose class value must be computed
* @return the newly computed value associated with this {@code ClassValue}, for the given class or interface
* @throws UndeclaredThrowableException if the {@code computeValue} method handle invocation throws something other than a {@code RuntimeException} or {@code Error}
* @throws UnsupportedOperationException if the {@code computeValue} method handle is null (subclasses must override)
* @see #get
* @see #remove
*/
protected T computeValue(Class<?> type) {
if (computeValue == null)
return null;
try {
return (T) (Object) computeValue.invokeGeneric(type);
} catch (Throwable ex) {
if (ex instanceof Error) throw (Error) ex;
if (ex instanceof RuntimeException) throw (RuntimeException) ex;
throw new UndeclaredThrowableException(ex);
}
}
private final MethodHandle computeValue;
/**
* Creates a new class value.
* Subclasses which use this constructor must override
* the {@link #computeValue computeValue} method,
* since the default {@code computeValue} method requires a method handle,
* which this constructor does not provide.
*/
protected ClassValue() {
this.computeValue = null;
}
/**
* Creates a new class value, whose {@link #computeValue computeValue} method
* will return the result of {@code computeValue.invokeGeneric(type)}.
* @throws NullPointerException if the method handle parameter is null
*/
public ClassValue(MethodHandle computeValue) {
computeValue.getClass(); // trigger NPE if null
this.computeValue = computeValue;
}
protected abstract T computeValue(Class<?> type);
/**
* Returns the value for the given class.
* If no value has yet been computed, it is obtained by
* by an invocation of the {@link #computeValue computeValue} method.
* an invocation of the {@link #computeValue computeValue} method.
* <p>
* The actual installation of the value on the class
* is performed atomically.
* At that point, if racing threads have
* At that point, if several racing threads have
* computed values, one is chosen, and returned to
* all the racing threads.
* <p>
* The {@code type} parameter is typically a class, but it may be any type,
* such as an interface, a primitive type (like {@code int.class}), or {@code void.class}.
* <p>
* In the absence of {@code remove} calls, a class value has a simple
* state diagram: uninitialized and initialized.
* When {@code remove} calls are made,
* the rules for value observation are more complex.
* See the documentation for {@link #remove remove} for more information.
*
* @param type the type whose class value must be computed or retrieved
* @return the current value associated with this {@code ClassValue}, for the given class or interface
* @throws NullPointerException if the argument is null
* @see #remove
* @see #computeValue
*/
public T get(Class<?> type) {
ClassValueMap map = getMap(type);
......@@ -119,12 +103,51 @@ public class ClassValue<T> {
* This may result in an additional invocation of the
* {@code computeValue computeValue} method for the given class.
* <p>
* If racing threads perform a combination of {@code get} and {@code remove} calls,
* the calls are serialized.
* A value produced by a call to {@code computeValue} will be discarded, if
* the corresponding {@code get} call was followed by a {@code remove} call
* before the {@code computeValue} could complete.
* In such a case, the {@code get} call will re-invoke {@code computeValue}.
* In order to explain the interaction between {@code get} and {@code remove} calls,
* we must model the state transitions of a class value to take into account
* the alternation between uninitialized and initialized states.
* To do this, number these states sequentially from zero, and note that
* uninitialized (or removed) states are numbered with even numbers,
* while initialized (or re-initialized) states have odd numbers.
* <p>
* When a thread {@code T} removes a class value in state {@code 2N},
* nothing happens, since the class value is already uninitialized.
* Otherwise, the state is advanced atomically to {@code 2N+1}.
* <p>
* When a thread {@code T} queries a class value in state {@code 2N},
* the thread first attempts to initialize the class value to state {@code 2N+1}
* by invoking {@code computeValue} and installing the resulting value.
* <p>
* When {@code T} attempts to install the newly computed value,
* if the state is still at {@code 2N}, the class value will be initialized
* with the computed value, advancing it to state {@code 2N+1}.
* <p>
* Otherwise, whether the new state is even or odd,
* {@code T} will discard the newly computed value
* and retry the {@code get} operation.
* <p>
* Discarding and retrying is an important proviso,
* since otherwise {@code T} could potentially install
* a disastrously stale value. For example:
* <ul>
* <li>{@code T} calls {@code CV.get(C)} and sees state {@code 2N}
* <li>{@code T} quickly computes a time-dependent value {@code V0} and gets ready to install it
* <li>{@code T} is hit by an unlucky paging or scheduling event, and goes to sleep for a long time
* <li>...meanwhile, {@code T2} also calls {@code CV.get(C)} and sees state {@code 2N}
* <li>{@code T2} quickly computes a similar time-dependent value {@code V1} and installs it on {@code CV.get(C)}
* <li>{@code T2} (or a third thread) then calls {@code CV.remove(C)}, undoing {@code T2}'s work
* <li> the previous actions of {@code T2} are repeated several times
* <li> also, the relevant computed values change over time: {@code V1}, {@code V2}, ...
* <li>...meanwhile, {@code T} wakes up and attempts to install {@code V0}; <em>this must fail</em>
* </ul>
* We can assume in the above scenario that {@code CV.computeValue} uses locks to properly
* observe the time-dependent states as it computes {@code V1}, etc.
* This does not remove the threat of a stale value, since there is a window of time
* between the return of {@code computeValue} in {@code T} and the installation
* of the the new value. No user synchronization is possible during this time.
*
* @param type the type whose class value must be removed
* @throws NullPointerException if the argument is null
*/
public void remove(Class<?> type) {
ClassValueMap map = getMap(type);
......@@ -137,9 +160,9 @@ public class ClassValue<T> {
/// Implementation...
/** The hash code for this type is based on the identity of the object,
* and is well-dispersed for power-of-two tables.
*/
// The hash code for this type is based on the identity of the object,
// and is well-dispersed for power-of-two tables.
/** @deprecated This override, which is implementation-specific, will be removed for PFD. */
public final int hashCode() { return hashCode; }
private final int hashCode = HASH_CODES.getAndAdd(0x61c88647);
private static final AtomicInteger HASH_CODES = new AtomicInteger();
......
jdk/src/share/classes/java/dyn/ConstantCallSite.java
浏览文件 @ d7393144
/*
* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
......@@ -32,16 +32,46 @@ package java.dyn;
* @author John Rose, JSR 292 EG
*/
public class ConstantCallSite extends CallSite {
/** Create a call site with a permanent target.
/**
* Creates a call site with a permanent target.
* @param target the target to be permanently associated with this call site
* @throws NullPointerException if the proposed target is null
*/
public ConstantCallSite(MethodHandle target) {
super(target);
}
/**
* Returns the target method of the call site, which behaves
* like a {@code final} field of the {@code ConstantCallSite}.
* That is, the the target is always the original value passed
* to the constructor call which created this instance.
*
* @return the immutable linkage state of this call site, a constant method handle
* @throws UnsupportedOperationException because this kind of call site cannot change its target
*/
@Override public final MethodHandle getTarget() {
return target;
}
/**
* Throw an {@link UnsupportedOperationException}, because this kind of call site cannot change its target.
* Always throws an {@link UnsupportedOperationException}.
* This kind of call site cannot change its target.
* @param ignore a new target proposed for the call site, which is ignored
* @throws UnsupportedOperationException because this kind of call site cannot change its target
*/
@Override public final void setTarget(MethodHandle ignore) {
throw new UnsupportedOperationException("ConstantCallSite");
}
/**
* Returns this call site's permanent target.
* Since that target will never change, this is a correct implementation
* of {@link CallSite#dynamicInvoker CallSite.dynamicInvoker}.
* @return the immutable linkage state of this call site, a constant method handle
*/
@Override
public final MethodHandle dynamicInvoker() {
return getTarget();
}
}
jdk/src/share/classes/java/dyn/InvokeDynamicBootstrapError.java
浏览文件 @ d7393144
......@@ -31,8 +31,8 @@ package java.dyn;
* {@linkplain BootstrapMethod bootstrap method},
* or the bootstrap method has
* failed to provide a
* {@linkplain CallSite} call site with a non-null {@linkplain MethodHandle target}
* of the correct {@linkplain MethodType method type}.
* {@linkplain CallSite call site} with a {@linkplain CallSite#getTarget target}
* of the correct {@linkplain MethodHandle#type method type}.
*
* @author John Rose, JSR 292 EG
* @since 1.7
......
jdk/src/share/classes/java/dyn/Linkage.java
浏览文件 @ d7393144
......@@ -101,8 +101,9 @@ public class Linkage {
/**
* <em>METHOD WILL BE REMOVED FOR PFD:</em>
* Invalidate all <code>invokedynamic</code> call sites everywhere.
* @deprecated Use {@linkplain CallSite#setTarget call site target setting}
* and {@link VolatileCallSite#invalidateAll call site invalidation} instead.
* @deprecated Use {@linkplain MutableCallSite#setTarget call site target setting},
* {@link MutableCallSite#syncAll call site update pushing},
* and {@link SwitchPoint#guardWithTest target switching} instead.
*/
public static
Object invalidateAll() {
......@@ -113,8 +114,9 @@ public class Linkage {
* <em>METHOD WILL BE REMOVED FOR PFD:</em>
* Invalidate all {@code invokedynamic} call sites in the bytecodes
* of any methods of the given class.
* @deprecated Use {@linkplain CallSite#setTarget call site target setting}
* and {@link VolatileCallSite#invalidateAll call site invalidation} instead.
* @deprecated Use {@linkplain MutableCallSite#setTarget call site target setting},
* {@link MutableCallSite#syncAll call site update pushing},
* and {@link SwitchPoint#guardWithTest target switching} instead.
*/
public static
Object invalidateCallerClass(Class<?> callerClass) {
......
jdk/src/share/classes/java/dyn/MethodHandle.java
浏览文件 @ d7393144
......@@ -34,7 +34,7 @@ import static java.dyn.MethodHandles.invokers; // package-private API
import static sun.dyn.MemberName.newIllegalArgumentException; // utility
/**
* A method handle is a typed, directly executable reference to a method,
* A method handle is a typed, directly executable reference to an underlying method,
* constructor, field, or similar low-level operation, with optional
* transformations of arguments or return values.
* These transformations are quite general, and include such patterns as
......@@ -48,105 +48,183 @@ import static sun.dyn.MemberName.newIllegalArgumentException; // utility
* will be removed before the Proposed Final Draft.
* Also, the final version will not include any public or
* protected constructors.</em>
* <p>
* Method handles are strongly typed according to signature.
* They are not distinguished by method name or enclosing class.
* A method handle must be invoked under a signature which matches
* the method handle's own {@linkplain MethodType method type}.
*
* <h3>Method handle contents</h3>
* Method handles are dynamically and strongly typed according to type descriptor.
* They are not distinguished by the name or defining class of their underlying methods.
* A method handle must be invoked using type descriptor which matches
* the method handle's own {@linkplain #type method type}.
* <p>
* Every method handle reports its type via the {@link #type type} accessor.
* The structure of this type is a series of classes, one of which is
* This type descriptor is a {@link java.dyn.MethodType MethodType} object,
* whose structure is a series of classes, one of which is
* the return type of the method (or {@code void.class} if none).
* <p>
* Every method handle appears as an object containing a method named
* {@link #invokeExact invokeExact}, whose signature exactly matches
* the method handle's type.
* A Java method call expression, which compiles to an
* {@code invokevirtual} instruction,
* can invoke this method from Java source code.
* A method handle's type controls the types of invocations it accepts,
* and the kinds of transformations that apply to it.
* <p>
* A method handle contains a pair of special invoker methods
* called {@link #invokeExact invokeExact} and {@link #invokeGeneric invokeGeneric}.
* Both invoker methods provide direct access to the method handle's
* underlying method, constructor, field, or other operation,
* as modified by transformations of arguments and return values.
* Both invokers accept calls which exactly match the method handle's own type.
* The {@code invokeGeneric} invoker also accepts a range of other call types.
* <p>
* Every call to a method handle specifies an intended method type,
* which must exactly match the type of the method handle.
* (The type is specified in the {@code invokevirtual} instruction,
* via a {@code CONSTANT_NameAndType} constant pool entry.)
* The call looks within the receiver object for a method
* named {@code invokeExact} of the intended method type.
* The call fails with a {@link WrongMethodTypeException}
* if the method does not exist, even if there is an {@code invokeExact}
* method of a closely similar signature.
* As with other kinds
* of methods in the JVM, signature matching during method linkage
* is exact, and does not allow for language-level implicit conversions
* such as {@code String} to {@code Object} or {@code short} to {@code int}.
* Method handles are immutable and have no visible state.
* Of course, they can be bound to underlying methods or data which exhibit state.
* With respect to the Java Memory Model, any method handle will behave
* as if all of its (internal) fields are final variables. This means that any method
* handle made visible to the application will always be fully formed.
* This is true even if the method handle is published through a shared
* variable in a data race.
* <p>
* Method handles cannot be subclassed by the user.
* Implementations may (or may not) create internal subclasses of {@code MethodHandle}
* which may be visible via the {@link java.lang.Object#getClass Object.getClass}
* operation. The programmer should not draw conclusions about a method handle
* from its specific class, as the method handle class hierarchy (if any)
* may change from time to time or across implementations from different vendors.
*
* <h3>Method handle compilation</h3>
* A Java method call expression naming {@code invokeExact} or {@code invokeGeneric}
* can invoke a method handle from Java source code.
* From the viewpoint of source code, these methods can take any arguments
* and their result can be cast to any return type.
* Formally this is accomplished by giving the invoker methods
* {@code Object} return types and variable-arity {@code Object} arguments,
* but they have an additional quality called "signature polymorphism"
* which connects this freedom of invocation directly to the JVM execution stack.
* <p>
* As is usual with virtual methods, source-level calls to {@code invokeExact}
* and {@code invokeGeneric} compile to an {@code invokevirtual} instruction.
* More unusually, the compiler must record the actual argument types,
* and may not perform method invocation conversions on the arguments.
* Instead, it must push them on the stack according to their own unconverted types.
* The method handle object itself is pushed on the stack before the arguments.
* The compiler then calls the method handle with a type descriptor which
* describes the argument and return types.
* <p>
* To issue a complete type descriptor, the compiler must also determine
* the return type. This is based on a cast on the method invocation expression,
* if there is one, or else {@code Object} if the invocation is an expression
* or else {@code void} if the invocation is a statement.
* The cast may be to a primitive type (but not {@code void}).
* <p>
* As a corner case, an uncasted {@code null} argument is given
* a type descriptor of {@code java.lang.Void}.
* The ambiguity with the type {@code Void} is harmless, since there are no references of type
* {@code Void} except the null reference.
*
* <h3>Method handle invocation</h3>
* The first time a {@code invokevirtual} instruction is executed
* it is linked, by symbolically resolving the names in the instruction
* and verifying that the method call is statically legal.
* This is true of calls to {@code invokeExact} and {@code invokeGeneric}.
* In this case, the type descriptor emitted by the compiler is checked for
* correct syntax and names it contains are resolved.
* Thus, an {@code invokevirtual} instruction which invokes
* a method handle will always link, as long
* as the type descriptor is syntactically well-formed
* and the types exist.
* <p>
* When the {@code invokevirtual} is executed after linking,
* the receiving method handle's type is first checked by the JVM
* to ensure that it matches the descriptor.
* If the type match fails, it means that the method which the
* caller is invoking is not present on the individual
* method handle being invoked.
* <p>
* In the case of {@code invokeExact}, the type descriptor of the invocation
* (after resolving symbolic type names) must exactly match the method type
* of the receiving method handle.
* In the case of {@code invokeGeneric}, the resolved type descriptor
* must be a valid argument to the receiver's {@link #asType asType} method.
* Thus, {@code invokeGeneric} is more permissive than {@code invokeExact}.
* <p>
* After type matching, a call to {@code invokeExact} directly
* and immediately invoke the method handle's underlying method
* (or other behavior, as the case may be).
* <p>
* Each individual method handle also contains a method named
* {@link #invokeGeneric invokeGeneric}, whose type is the same
* as {@code invokeExact}, and is therefore also reported by
* the {@link #type type} accessor.
* A call to {@code invokeGeneric} works the same as a call to
* {@code invokeExact}, if the signature specified by the caller
* {@code invokeExact}, if the type descriptor specified by the caller
* exactly matches the method handle's own type.
* If there is a type mismatch, {@code invokeGeneric} attempts
* to adjust the type of the target method handle
* (as if by a call to {@link #asType asType})
* to obtain an exactly invokable target.
* to adjust the type of the receiving method handle,
* as if by a call to {@link #asType asType},
* to obtain an exactly invokable method handle {@code M2}.
* This allows a more powerful negotiation of method type
* between caller and callee.
* <p>
* A method handle is an unrestricted capability to call a method.
* A method handle can be formed on a non-public method by a class
* that has access to that method; the resulting handle can be used
* in any place by any caller who receives a reference to it. Thus, access
* checking is performed when the method handle is created, not
* (as in reflection) every time it is called. Handles to non-public
* methods, or in non-public classes, should generally be kept secret.
* They should not be passed to untrusted code unless their use from
* the untrusted code would be harmless.
* (Note: The adjusted method handle {@code M2} is not directly observable,
* and implementations are therefore not required to materialize it.)
*
* <h3>Invocation checking</h3>
* In typical programs, method handle type matching will usually succeed.
* But if a match fails, the JVM will throw a {@link WrongMethodTypeException},
* either directly (in the case of {@code invokeExact}) or indirectly as if
* by a failed call to {@code asType} (in the case of {@code invokeGeneric}).
* <p>
* Bytecode in the JVM can directly call a method handle's
* {@code invokeExact} method from an {@code invokevirtual} instruction.
* The receiver class type must be {@code MethodHandle} and the method name
* must be {@code invokeExact}. The signature of the invocation
* (after resolving symbolic type names) must exactly match the method type
* of the target method.
* Similarly, bytecode can directly call a method handle's {@code invokeGeneric}
* method. The signature of the invocation (after resolving symbolic type names)
* must either exactly match the method type or be a valid argument to
* the target's {@link #asType asType} method.
* Thus, a method type mismatch which might show up as a linkage error
* in a statically typed program can show up as
* a dynamic {@code WrongMethodTypeException}
* in a program which uses method handles.
* <p>
* Every {@code invokeExact} and {@code invokeGeneric} method always
* throws {@link java.lang.Throwable Throwable},
* which is to say that there is no static restriction on what a method handle
* can throw. Since the JVM does not distinguish between checked
* and unchecked exceptions (other than by their class, of course),
* there is no particular effect on bytecode shape from ascribing
* checked exceptions to method handle invocations. But in Java source
* code, methods which perform method handle calls must either explicitly
* throw {@code java.lang.Throwable Throwable}, or else must catch all
* throwables locally, rethrowing only those which are legal in the context,
* and wrapping ones which are illegal.
* Because method types contain "live" {@code Class} objects,
* method type matching takes into account both types names and class loaders.
* Thus, even if a method handle {@code M} is created in one
* class loader {@code L1} and used in another {@code L2},
* method handle calls are type-safe, because the caller's type
* descriptor, as resolved in {@code L2},
* is matched against the original callee method's type descriptor,
* as resolved in {@code L1}.
* The resolution in {@code L1} happens when {@code M} is created
* and its type is assigned, while the resolution in {@code L2} happens
* when the {@code invokevirtual} instruction is linked.
* <p>
* Apart from the checking of type descriptors,
* a method handle's capability to call its underlying method is unrestricted.
* If a method handle is formed on a non-public method by a class
* that has access to that method, the resulting handle can be used
* in any place by any caller who receives a reference to it.
* <p>
* Bytecode in the JVM can directly obtain a method handle
* for any accessible method from a {@code ldc} instruction
* which refers to a {@code CONSTANT_MethodHandle} constant pool entry.
* (Each such entry refers directly to a {@code CONSTANT_Methodref},
* Unlike with the Core Reflection API, where access is checked every time
* a reflective method is invoked,
* method handle access checking is performed
* <a href="MethodHandles.Lookup.html#access">when the method handle is created</a>.
* In the case of {@code ldc} (see below), access checking is performed as part of linking
* the constant pool entry underlying the constant method handle.
* <p>
* Thus, handles to non-public methods, or to methods in non-public classes,
* should generally be kept secret.
* They should not be passed to untrusted code unless their use from
* the untrusted code would be harmless.
*
* <h3>Method handle creation</h3>
* Java code can create a method handle that directly accesses
* any method, constructor, or field that is accessible to that code.
* This is done via a reflective, capability-based API called
* {@link java.dyn.MethodHandles.Lookup MethodHandles.Lookup}
* For example, a static method handle can be obtained
* from {@link java.dyn.MethodHandles.Lookup#findStatic Lookup.findStatic}.
* There are also conversion methods from Core Reflection API objects,
* such as {@link java.dyn.MethodHandles.Lookup#unreflect Lookup.unreflect}.
* <p>
* Like classes and strings, method handles that correspond to accessible
* fields, methods, and constructors can also be represented directly
* in a class file's constant pool as constants to be loaded by {@code ldc} bytecodes.
* A new type of constant pool entry, {@code CONSTANT_MethodHandle},
* refers directly to an associated {@code CONSTANT_Methodref},
* {@code CONSTANT_InterfaceMethodref}, or {@code CONSTANT_Fieldref}
* constant pool entry.
* For more details, see the <a href="package-summary.html#mhcon">package summary</a>.)
* (For more details on method handle constants,
* see the <a href="package-summary.html#mhcon">package summary</a>.)
* <p>
* Method handles produced by lookups or constant loads from methods or
* constructors with the variable arity modifier bit ({@code 0x0080})
* have a corresponding variable arity, as if they were defined with
* the help of {@link #asVarargsCollector asVarargsCollector}.
* <p>
* Java code can also use a reflective API called
* {@link java.dyn.MethodHandles.Lookup MethodHandles.Lookup}
* for creating and calling method handles.
* For example, a static method handle can be obtained
* from {@link java.dyn.MethodHandles.Lookup#findStatic Lookup.findStatic}.
* There are also bridge methods from Core Reflection API objects,
* such as {@link java.dyn.MethodHandles.Lookup#unreflect Lookup.ureflect}.
* <p>
* A method reference may refer either to a static or non-static method.
* In the non-static case, the method handle type includes an explicit
* receiver argument, prepended before any other arguments.
......@@ -158,64 +236,141 @@ import static sun.dyn.MemberName.newIllegalArgumentException; // utility
* When a method handle to a virtual method is invoked, the method is
* always looked up in the receiver (that is, the first argument).
* <p>
* A non-virtual method handles to a specific virtual method implementation
* A non-virtual method handle to a specific virtual method implementation
* can also be created. These do not perform virtual lookup based on
* receiver type. Such a method handle simulates the effect of
* an {@code invokespecial} instruction to the same method.
* <p>
*
* <h3>Usage examples</h3>
* Here are some examples of usage:
* <p><blockquote><pre>
Object x, y; String s; int i;
MethodType mt; MethodHandle mh;
MethodHandles.Lookup lookup = MethodHandles.lookup();
// mt is {(char,char) =&gt; String}
// mt is (char,char)String
mt = MethodType.methodType(String.class, char.class, char.class);
mh = lookup.findVirtual(String.class, "replace", mt);
// (Ljava/lang/String;CC)Ljava/lang/String;
s = (String) mh.invokeExact("daddy",'d','n');
// invokeExact(Ljava/lang/String;CC)Ljava/lang/String;
assert(s.equals("nanny"));
// weakly typed invocation (using MHs.invoke)
s = (String) mh.invokeWithArguments("sappy", 'p', 'v');
assert(s.equals("savvy"));
// mt is {Object[] =&gt; List}
// mt is (Object[])List
mt = MethodType.methodType(java.util.List.class, Object[].class);
mh = lookup.findStatic(java.util.Arrays.class, "asList", mt);
assert(mh.isVarargsCollector());
x = mh.invokeGeneric("one", "two");
// invokeGeneric(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/Object;
assert(x.equals(java.util.Arrays.asList("one","two")));
// mt is {(Object,Object,Object) =&gt; Object}
// mt is (Object,Object,Object)Object
mt = MethodType.genericMethodType(3);
mh = MethodHandles.collectArguments(mh, mt);
// mt is {(Object,Object,Object) =&gt; Object}
// (Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
mh = mh.asType(mt);
x = mh.invokeExact((Object)1, (Object)2, (Object)3);
// invokeExact(Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
assert(x.equals(java.util.Arrays.asList(1,2,3)));
// mt is { =&gt; int}
mt = MethodType.methodType(int.class);
mh = lookup.findVirtual(java.util.List.class, "size", mt);
// (Ljava/util/List;)I
i = (int) mh.invokeExact(java.util.Arrays.asList(1,2,3));
// invokeExact(Ljava/util/List;)I
assert(i == 3);
mt = MethodType.methodType(void.class, String.class);
mh = lookup.findVirtual(java.io.PrintStream.class, "println", mt);
mh.invokeExact(System.out, "Hello, world.");
// (Ljava/io/PrintStream;Ljava/lang/String;)V
// invokeExact(Ljava/io/PrintStream;Ljava/lang/String;)V
* </pre></blockquote>
* Each of the above calls generates a single invokevirtual instruction
* with the name {@code invoke} and the type descriptors indicated in the comments.
* The argument types are taken directly from the actual arguments,
* while the return type is taken from the cast immediately applied to the call.
* This cast may be to a primitive.
* If it is missing, the type defaults to {@code Object} if the call
* occurs in a context which uses the return value.
* If the call occurs as a statement, a cast is impossible,
* and there is no return type; the call is {@code void}.
* Each of the above calls to {@code invokeExact} or {@code invokeGeneric}
* generates a single invokevirtual instruction with
* the type descriptor indicated in the following comment.
*
* <h3>Exceptions</h3>
* The methods {@code invokeExact} and {@code invokeGeneric} are declared
* to throw {@link java.lang.Throwable Throwable},
* which is to say that there is no static restriction on what a method handle
* can throw. Since the JVM does not distinguish between checked
* and unchecked exceptions (other than by their class, of course),
* there is no particular effect on bytecode shape from ascribing
* checked exceptions to method handle invocations. But in Java source
* code, methods which perform method handle calls must either explicitly
* throw {@code java.lang.Throwable Throwable}, or else must catch all
* throwables locally, rethrowing only those which are legal in the context,
* and wrapping ones which are illegal.
*
* <h3><a name="polysig"></a>Signature polymorphism</h3>
* The unusual compilation and linkage behavior of
* {@code invokeExact} and {@code invokeGeneric}
* is referenced by the term <em>signature polymorphism</em>.
* A signature polymorphic method is one which can operate with
* any of a wide range of call signatures and return types.
* In order to make this work, both the Java compiler and the JVM must
* give special treatment to signature polymorphic methods.
* <p>
* In source code, a call to a signature polymorphic method will
* compile, regardless of the requested type descriptor.
* As usual, the Java compiler emits an {@code invokevirtual}
* instruction with the given type descriptor against the named method.
* The unusual part is that the type descriptor is derived from
* the actual argument and return types, not from the method declaration.
* <p>
* When the JVM processes bytecode containing signature polymorphic calls,
* it will successfully link any such call, regardless of its type descriptor.
* (In order to retain type safety, the JVM will guard such calls with suitable
* dynamic type checks, as described elsewhere.)
* <p>
* Bytecode generators, including the compiler back end, are required to emit
* untransformed type descriptors for these methods.
* Tools which determine symbolic linkage are required to accept such
* untransformed descriptors, without reporting linkage errors.
*
* <h3>Interoperation between method handles and the Core Reflection API</h3>
* Using factory methods in the {@link java.dyn.MethodHandles.Lookup Lookup} API,
* any class member represented by a Core Reflection API object
* can be converted to a behaviorally equivalent method handle.
* For example, a reflective {@link java.lang.reflect.Method Method} can
* be converted to a method handle using
* {@link java.dyn.MethodHandles.Lookup#unreflect Lookup.unreflect}.
* The resulting method handles generally provide more direct and efficient
* access to the underlying class members.
* <p>
* As a special case,
* when the Core Reflection API is used to view the signature polymorphic
* methods {@code invokeExact} or {@code invokeGeneric} in this class,
* they appear as single, non-polymorphic native methods.
* Calls to these native methods do not result in method handle invocations.
* Since {@code invokevirtual} instructions can natively
* invoke method handles under any type descriptor, this reflective view conflicts
* with the normal presentation via bytecodes.
* Thus, these two native methods, as viewed by
* {@link java.lang.Class#getDeclaredMethod Class.getDeclaredMethod},
* are placeholders only.
* If invoked via {@link java.lang.reflect.Method#invoke Method.invoke},
* they will throw {@code UnsupportedOperationException}.
* <p>
* In order to obtain an invoker method for a particular type descriptor,
* use {@link java.dyn.MethodHandles#exactInvoker MethodHandles.exactInvoker},
* or {@link java.dyn.MethodHandles#genericInvoker MethodHandles.genericInvoker}.
* The {@link java.dyn.MethodHandles.Lookup#findVirtual Lookup.findVirtual}
* API is also able to return a method handle
* to call {@code invokeExact} or {@code invokeGeneric},
* for any specified type descriptor .
*
* <h3>Interoperation between method handles and Java generics</h3>
* A method handle can be obtained on a method, constructor, or field
* which is declared with Java generic types.
* As with the Core Reflection API, the type of the method handle
* will constructed from the erasure of the source-level type.
* When a method handle is invoked, the types of its arguments
* or the return value cast type may be generic types or type instances.
* If this occurs, the compiler will replace those
* types by their erasures when when it constructs the type descriptor
* for the {@code invokevirtual} instruction.
* <p>
* <em>A note on generic typing:</em> Method handles do not represent
* their function types in terms of Java parameterized (generic) types,
* because there are three mismatches between function types and parameterized
* Method handles do not represent
* their function-like types in terms of Java parameterized (generic) types,
* because there are three mismatches between function-like types and parameterized
* Java types.
* <ol>
* <ul>
* <li>Method types range over all possible arities,
* from no arguments to up to 255 of arguments (a limit imposed by the JVM).
* Generics are not variadic, and so cannot represent this.</li>
......@@ -225,29 +380,7 @@ mh.invokeExact(System.out, "Hello, world.");
* often generic across a wide range of function types, including
* those of multiple arities. It is impossible to represent such
* genericity with a Java type parameter.</li>
* </ol>
* Signature polymorphic methods in this class appear to be documented
* as having type parameters for return types and a parameter, but that is
* merely a documentation convention. These type parameters do
* not play a role in type-checking method handle invocations.
* <p>
* Like classes and strings, method handles that correspond to accessible
* fields, methods, and constructors can be represented directly
* in a class file's constant pool as constants to be loaded by {@code ldc} bytecodes.
* Loading such a constant causes the component classes of its type to be loaded as necessary.
* <p>
* Method handles cannot be subclassed by the user.
* Implementations may (or may not) create internal subclasses of {@code MethodHandle}
* which may be visible via the {@code java.lang.Object#getClass Object.getClass}
* operation. The programmer should not draw conclusions about a method handle
* from its specific class, as the method handle class hierarchy (if any)
* may change from time to time or across implementations from different vendors.
* <p>
* With respect to the Java Memory Model, any method handle will behave
* as if all of its fields are final variables. This means that any method
* handle made visible to the application will always be fully formed.
* This is true even if the method handle is published through a shared
* variables in a data race.
* </ul>
*
* @see MethodType
* @see MethodHandles
......@@ -259,6 +392,7 @@ public abstract class MethodHandle
extends MethodHandleImpl
{
private static Access IMPL_TOKEN = Access.getToken();
static { MethodHandleImpl.initStatics(); }
// interface MethodHandle<R throws X extends Exception,A...>
// { MethodType<R throws X,A...> type(); public R invokeExact(A...) throws X; }
......@@ -278,7 +412,7 @@ public abstract class MethodHandle
* Every invocation of this method handle via {@code invokeExact} must exactly match this type.
* @return the method handle type
*/
public final MethodType type() {
public MethodType type() {
return type;
}
......@@ -315,20 +449,27 @@ public abstract class MethodHandle
}
/**
* Invoke the method handle, allowing any caller signature, but requiring an exact signature match.
* The signature at the call site of {@code invokeExact} must
* Invoke the method handle, allowing any caller type descriptor, but requiring an exact type match.
* The type descriptor at the call site of {@code invokeExact} must
* exactly match this method handle's {@link #type type}.
* No conversions are allowed on arguments or return values.
* @throws WrongMethodTypeException if the target's type is not identical with the caller's type signature
* <p>
* When this method is observed via the Core Reflection API,
* it will appear as a single native method, taking an object array and returning an object.
* If this native method is invoked directly via
* {@link java.lang.reflect.Method#invoke Method.invoke}, via JNI,
* or indirectly via {@link java.dyn.MethodHandles.Lookup#unreflect Lookup.unreflect},
* it will throw an {@code UnsupportedOperationException}.
* @throws WrongMethodTypeException if the target's type is not identical with the caller's type descriptor
* @throws Throwable anything thrown by the underlying method propagates unchanged through the method handle call
*/
public final native @PolymorphicSignature Object invokeExact(Object... args) throws Throwable;
/**
* Invoke the method handle, allowing any caller signature,
* Invoke the method handle, allowing any caller type descriptor,
* and optionally performing conversions on arguments and return values.
* <p>
* If the call site signature exactly matches this method handle's {@link #type type},
* If the call site type descriptor exactly matches this method handle's {@link #type type},
* the call proceeds as if by {@link #invokeExact invokeExact}.
* <p>
* Otherwise, the call proceeds as if this method handle were first
......@@ -341,12 +482,19 @@ public abstract class MethodHandle
* adaptations directly on the caller's arguments,
* and call the target method handle according to its own exact type.
* <p>
* The signature at the call site of {@code invokeGeneric} must
* The type descriptor at the call site of {@code invokeGeneric} must
* be a valid argument to the receivers {@code asType} method.
* In particular, the caller must specify the same argument arity
* as the callee's type,
* if the callee is not a {@linkplain #asVarargsCollector variable arity collector}.
* @throws WrongMethodTypeException if the target's type cannot be adjusted to the caller's type signature
* <p>
* When this method is observed via the Core Reflection API,
* it will appear as a single native method, taking an object array and returning an object.
* If this native method is invoked directly via
* {@link java.lang.reflect.Method#invoke Method.invoke}, via JNI,
* or indirectly via {@link java.dyn.MethodHandles.Lookup#unreflect Lookup.unreflect},
* it will throw an {@code UnsupportedOperationException}.
* @throws WrongMethodTypeException if the target's type cannot be adjusted to the caller's type descriptor
* @throws ClassCastException if the target's type can be adjusted to the caller, but a reference cast fails
* @throws Throwable anything thrown by the underlying method propagates unchanged through the method handle call
*/
......@@ -390,13 +538,19 @@ public abstract class MethodHandle
* MethodHandle invoker = MethodHandles.spreadInvoker(this.type(), 0);
* Object result = invoker.invokeExact(this, arguments);
* </pre></blockquote>
* <p>
* Unlike the signature polymorphic methods {@code invokeExact} and {@code invokeGeneric},
* {@code invokeWithArguments} can be accessed normally via the Core Reflection API and JNI.
* It can therefore be used as a bridge between native or reflective code and method handles.
*
* @param arguments the arguments to pass to the target
* @return the result returned by the target
* @throws WrongMethodTypeException if the target's type cannot be adjusted to take the arguments
* @throws ClassCastException if an argument cannot be converted by reference casting
* @throws WrongMethodTypeException if the target's type cannot be adjusted to take the given number of {@code Object} arguments
* @throws Throwable anything thrown by the target method invocation
* @see MethodHandles#spreadInvoker
*/
public final Object invokeWithArguments(Object... arguments) throws Throwable {
public Object invokeWithArguments(Object... arguments) throws Throwable {
int argc = arguments == null ? 0 : arguments.length;
MethodType type = type();
if (type.parameterCount() != argc) {
......@@ -404,7 +558,7 @@ public abstract class MethodHandle
return asType(MethodType.genericMethodType(argc)).invokeWithArguments(arguments);
}
if (argc <= 10) {
MethodHandle invoker = MethodHandles.invokers(type).genericInvoker();
MethodHandle invoker = invokers(type).genericInvoker();
switch (argc) {
case 0: return invoker.invokeExact(this);
case 1: return invoker.invokeExact(this,
......@@ -447,15 +601,7 @@ public abstract class MethodHandle
return invoker.invokeExact(this, arguments);
}
/** Equivalent to {@code invokeWithArguments(arguments.toArray())}. */
public final Object invokeWithArguments(java.util.List<?> arguments) throws Throwable {
return invokeWithArguments(arguments.toArray());
}
@Deprecated
public final Object invokeVarargs(Object... arguments) throws Throwable {
return invokeWithArguments(arguments);
}
@Deprecated
public final Object invokeVarargs(java.util.List<?> arguments) throws Throwable {
public Object invokeWithArguments(java.util.List<?> arguments) throws Throwable {
return invokeWithArguments(arguments.toArray());
}
......@@ -524,7 +670,7 @@ public abstract class MethodHandle
* @throws WrongMethodTypeException if the implied {@code asType} call fails
* @see #asCollector
*/
public final MethodHandle asSpreader(Class<?> arrayType, int arrayLength) {
public MethodHandle asSpreader(Class<?> arrayType, int arrayLength) {
Class<?> arrayElement = arrayType.getComponentType();
if (arrayElement == null) throw newIllegalArgumentException("not an array type");
MethodType oldType = type();
......@@ -575,7 +721,7 @@ public abstract class MethodHandle
* @see #asSpreader
* @see #asVarargsCollector
*/
public final MethodHandle asCollector(Class<?> arrayType, int arrayLength) {
public MethodHandle asCollector(Class<?> arrayType, int arrayLength) {
Class<?> arrayElement = arrayType.getComponentType();
if (arrayElement == null) throw newIllegalArgumentException("not an array type");
MethodType oldType = type();
......@@ -699,6 +845,7 @@ assertEquals(1, ls.size());
assertEquals("[three, thee, tee]", Arrays.toString((Object[])ls.get(0)));
* </pre></blockquote>
* <p style="font-size:smaller;">
* <em>Discussion:</em>
* These rules are designed as a dynamically-typed variation
* of the Java rules for variable arity methods.
* In both cases, callers to a variable arity method or method handle
......@@ -710,7 +857,7 @@ assertEquals("[three, thee, tee]", Arrays.toString((Object[])ls.get(0)));
* array or a single element of an array to be collected.
* Note that the dynamic type of the trailing argument has no
* effect on this decision, only a comparison between the static
* type signature of the call site and the type of the method handle.)
* type descriptor of the call site and the type of the method handle.)
* <p style="font-size:smaller;">
* As a result of the previously stated rules, the variable arity behavior
* of a method handle may be suppressed, by binding it to the exact invoker
......@@ -719,9 +866,7 @@ assertEquals("[three, thee, tee]", Arrays.toString((Object[])ls.get(0)));
MethodHandle vamh = publicLookup()
.findStatic(Arrays.class, "asList", methodType(List.class, Object[].class))
.asVarargsCollector(Object[].class);
MethodHandle invokeExact = publicLookup()
.findVirtual(MethodHandle.class, "invokeExact", vamh.type());
MethodHandle mh = invokeExact.bindTo(vamh);
MethodHandle mh = MethodHandles.exactInvoker(vamh.type()).bindTo(vamh);
assert(vamh.type().equals(mh.type()));
assertEquals("[1, 2, 3]", vamh.invokeGeneric(1,2,3).toString());
boolean failed = false;
......@@ -731,12 +876,14 @@ assert(failed);
* </pre></blockquote>
* This transformation has no behavioral effect if the method handle is
* not of variable arity.
*
* @param arrayType often {@code Object[]}, the type of the array argument which will collect the arguments
* @return a new method handle which can collect any number of trailing arguments
* into an array, before calling the original method handle
* @throws IllegalArgumentException if {@code arrayType} is not an array type
* or {@code arrayType} is not assignable to this method handle's trailing parameter type
* @see #asCollector
* @see #isVarargsCollector
*/
public MethodHandle asVarargsCollector(Class<?> arrayType) {
Class<?> arrayElement = arrayType.getComponentType();
......@@ -756,6 +903,7 @@ assert(failed);
* which resolves to a variable arity Java method or constructor
* </ul>
* @return true if this method handle accepts more than one arity of {@code invokeGeneric} calls
* @see #asVarargsCollector
*/
public boolean isVarargsCollector() {
return false;
......@@ -785,7 +933,7 @@ assert(failed);
* to the leading parameter type of the target
* @see MethodHandles#insertArguments
*/
public final MethodHandle bindTo(Object x) {
public MethodHandle bindTo(Object x) {
return MethodHandles.insertArguments(this, 0, x);
}
......
jdk/src/share/classes/java/dyn/MethodHandles.java
浏览文件 @ d7393144
......@@ -29,6 +29,7 @@ import java.lang.reflect.*;
import sun.dyn.Access;
import sun.dyn.MemberName;
import sun.dyn.MethodHandleImpl;
import sun.dyn.WrapperInstance;
import sun.dyn.util.ValueConversions;
import sun.dyn.util.VerifyAccess;
import sun.dyn.util.Wrapper;
......@@ -45,10 +46,10 @@ import static sun.dyn.MemberName.newNoAccessException;
* This class consists exclusively of static methods that operate on or return
* method handles. They fall into several categories:
* <ul>
* <li>Factory methods which create method handles for methods and fields.
* <li>Invoker methods which can invoke method handles on dynamically typed arguments and/or varargs arrays.
* <li>Combinator methods, which combine or transforming pre-existing method handles into new ones.
* <li>Factory methods which create method handles that emulate other common JVM operations or control flow patterns.
* <li>Lookup methods which help create method handles for methods and fields.
* <li>Combinator methods, which combine or transform pre-existing method handles into new ones.
* <li>Other factory methods to create method handles that emulate other common JVM operations or control flow patterns.
* <li>Wrapper methods which can convert between method handles and other function-like "SAM types".
* </ul>
* <p>
* @author John Rose, JSR 292 EG
......@@ -97,34 +98,130 @@ public class MethodHandles {
* when the creation requires access checking.
* Method handles do not perform
* access checks when they are called, but rather when they are created.
* (This is a major difference
* from reflective {@link Method}, which performs access checking
* against every caller, on every call.)
* Therefore, method handle access
* restrictions must be enforced when a method handle is created.
* The caller class against which those restrictions are enforced
* is known as the {@linkplain #lookupClass lookup class}.
* A lookup object embodies an
* authenticated lookup class, and can be used to create any number
* <p>
* A lookup class which needs to create method handles will call
* {@link MethodHandles#lookup MethodHandles.lookup} to create a factory for itself.
* When the {@code Lookup} factory object is created, the identity of the lookup class is
* determined, and securely stored in the {@code Lookup} object.
* The lookup class (or its delegates) may then use factory methods
* on the {@code Lookup} object to create method handles for access-checked members.
* This includes all methods, constructors, and fields which are allowed to the lookup class,
* even private ones.
* <p>
* The factory methods on a {@code Lookup} object correspond to all major
* use cases for methods, constructors, and fields.
* Here is a summary of the correspondence between these factory methods and
* the behavior the resulting method handles:
* <code>
* <table border=1 cellpadding=5 summary="lookup method behaviors">
* <tr><th>lookup expression</th><th>member</th><th>behavior</th></tr>
* <tr>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findGetter lookup.findGetter(C.class,"f",FT.class)}</td>
* <td>FT f;</td><td>(T) this.f;</td>
* </tr>
* <tr>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findStaticGetter lookup.findStaticGetter(C.class,"f",FT.class)}</td>
* <td>static<br>FT f;</td><td>(T) C.f;</td>
* </tr>
* <tr>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findSetter lookup.findSetter(C.class,"f",FT.class)}</td>
* <td>FT f;</td><td>this.f = x;</td>
* </tr>
* <tr>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findStaticSetter lookup.findStaticSetter(C.class,"f",FT.class)}</td>
* <td>static<br>FT f;</td><td>C.f = arg;</td>
* </tr>
* <tr>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findVirtual lookup.findVirtual(C.class,"m",MT)}</td>
* <td>T m(A*);</td><td>(T) this.m(arg*);</td>
* </tr>
* <tr>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findStatic lookup.findStatic(C.class,"m",MT)}</td>
* <td>static<br>T m(A*);</td><td>(T) C.m(arg*);</td>
* </tr>
* <tr>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findSpecial lookup.findSpecial(C.class,"m",MT,this.class)}</td>
* <td>T m(A*);</td><td>(T) super.m(arg*);</td>
* </tr>
* <tr>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findConstructor lookup.findConstructor(C.class,MT)}</td>
* <td>C(A*);</td><td>(T) new C(arg*);</td>
* </tr>
* <tr>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#unreflectGetter lookup.unreflectGetter(aField)}</td>
* <td>(static)?<br>FT f;</td><td>(FT) aField.get(thisOrNull);</td>
* </tr>
* <tr>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#unreflectSetter lookup.unreflectSetter(aField)}</td>
* <td>(static)?<br>FT f;</td><td>aField.set(thisOrNull, arg);</td>
* </tr>
* <tr>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#unreflect lookup.unreflect(aMethod)}</td>
* <td>(static)?<br>T m(A*);</td><td>(T) aMethod.invoke(thisOrNull, arg*);</td>
* </tr>
* <tr>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#unreflectConstructor lookup.unreflectConstructor(aConstructor)}</td>
* <td>C(A*);</td><td>(C) aConstructor.newInstance(arg*);</td>
* </tr>
* <tr>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#unreflect lookup.unreflect(aMethod)}</td>
* <td>(static)?<br>T m(A*);</td><td>(T) aMethod.invoke(thisOrNull, arg*);</td>
* </tr>
* </table>
* </code>
* Here, the type {@code C} is the class or interface being searched for a member,
* documented as a parameter named {@code refc} in the lookup methods.
* The method or constructor type {@code MT} is composed from the return type {@code T}
* and the sequence of argument types {@code A*}.
* Both {@code MT} and the field type {@code FT} are documented as a parameter named {@code type}.
* The formal parameter {@code this} stands for the self-reference of type {@code C};
* if it is present, it is always the leading argument to the method handle invocation.
* The name {@code arg} stands for all the other method handle arguments.
* In the code examples for the Core Reflection API, the name {@code thisOrNull}
* stands for a null reference if the accessed method or field is static,
* and {@code this} otherwise.
* The names {@code aMethod}, {@code aField}, and {@code aConstructor} stand
* for reflective objects corresponding to the given members.
* <p>
* The equivalence between looked-up method handles and underlying
* class members can break down in a few ways:
* <ul>
* <li>If {@code C} is not symbolically accessible from the lookup class's loader,
* the lookup can still succeed, even when there is no equivalent
* Java expression or bytecoded constant.
* <li>Likewise, if {@code T} or {@code MT}
* is not symbolically accessible from the lookup class's loader,
* the lookup can still succeed.
* For example, lookups for {@code MethodHandle.invokeExact} and
* {@code MethodHandle.invokeGeneric} will always succeed, regardless of requested type.
* </ul>
*
* <h3><a name="access"></a>Access checking</h3>
* Access checks are applied in the factory methods of {@code Lookup},
* when a method handle is created.
* This is a key difference from the Core Reflection API, since
* {@link java.lang.reflect.Method#invoke Method.invoke}
* performs access checking against every caller, on every call.
* <p>
* All access checks start from a {@code Lookup} object, which
* compares its recorded lookup class against all requests to
* create method handles.
* A single {@code Lookup} object can be used to create any number
* of access-checked method handles, all checked against a single
* lookup class.
* <p>
* A class which needs to create method handles will call
* {@link MethodHandles#lookup MethodHandles.lookup} to create a factory for itself.
* It may then use this factory to create method handles on
* all of its methods, including private ones.
* It may also delegate the lookup (e.g., to a metaobject protocol)
* by passing the lookup object to other code.
* If this other code creates method handles, they will be access
* checked against the original lookup class, and not with any higher
* privileges.
* A {@code Lookup} object can be shared with other trusted code,
* such as a metaobject protocol.
* A shared {@code Lookup} object delegates the capability
* to create method handles on private members of the lookup class.
* Even if privileged code uses the {@code Lookup} object,
* the access checking is confined to the privileges of the
* original lookup class.
* <p>
* Access checks only apply to named and reflected methods.
* Other method handle creation methods, such as
* {@link #convertArguments MethodHandles.convertArguments},
* do not require any access checks, and can be done independently
* of any lookup class.
* <h3>How access errors are handled</h3>
* A lookup can fail, because
* the containing class is not accessible to the lookup class, or
* because the desired class member is missing, or because the
......@@ -134,13 +231,13 @@ public class MethodHandles {
* thrown from the attempted lookup.
* <p>
* In general, the conditions under which a method handle may be
* created for a method {@code M} are exactly as restrictive as the conditions
* under which the lookup class could have compiled a call to {@code M},
* or could have compiled an {@code ldc} instruction loading a
* {@code CONSTANT_MethodHandle} of M.
* looked up for a method {@code M} are exactly equivalent to the conditions
* under which the lookup class could have compiled and resolved a call to {@code M}.
* And the effect of invoking the method handle resulting from the lookup
* is exactly equivalent to executing the compiled and resolved call to {@code M}.
* The same point is true of fields and constructors.
* <p>
* In some cases, this access is obtained by the Java compiler by creating
* In some cases, access between nested classes is obtained by the Java compiler by creating
* an wrapper method to access a private method of another class
* in the same top-level declaration.
* For example, a nested class {@code C.D}
......@@ -152,6 +249,14 @@ public class MethodHandles {
* A workaround for this limitation is the {@link Lookup#in Lookup.in} method,
* which can transform a lookup on {@code C.E} into one on any of those other
* classes, without special elevation of privilege.
* <p>
* Access checks only apply to named and reflected methods,
* constructors, and fields.
* Other method handle creation methods, such as
* {@link #convertArguments MethodHandles.convertArguments},
* do not require any access checks, and are done
* with static methods of {@link MethodHandles},
* independently of any {@code Lookup} object.
*/
public static final
class Lookup {
......@@ -197,12 +302,12 @@ public class MethodHandles {
return (mods != 0) ? mods : PACKAGE;
}
/** Which class is performing the lookup? It is this class against
/** Tells which class is performing the lookup. It is this class against
* which checks are performed for visibility and access permissions.
* <p>
* The class implies a maximum level of access permission,
* but the permissions may be additionally limited by the bitmask
* {@link #lookupModes}, which controls whether non-public members
* {@link #lookupModes lookupModes}, which controls whether non-public members
* can be accessed.
*/
public Class<?> lookupClass() {
......@@ -214,7 +319,7 @@ public class MethodHandles {
return (allowedModes == TRUSTED) ? null : lookupClass;
}
/** Which types of members can this lookup object produce?
/** Tells which access-protection classes of members this lookup object can produce.
* The result is a bit-mask of the bits
* {@linkplain #PUBLIC PUBLIC (0x01)},
* {@linkplain #PRIVATE PRIVATE (0x02)},
......@@ -260,7 +365,7 @@ public class MethodHandles {
}
/**
* Create a lookup on the specified new lookup class.
* Creates a lookup on the specified new lookup class.
* The resulting object will report the specified
* class as its own {@link #lookupClass lookupClass}.
* <p>
......@@ -278,6 +383,10 @@ public class MethodHandles {
* then no members, not even public members, will be accessible.
* (In all other cases, public members will continue to be accessible.)
* </ul>
*
* @param requestedLookupClass the desired lookup class for the new lookup object
* @return a lookup object which reports the desired lookup class
* @throws NullPointerException if the argument is null
*/
public Lookup in(Class<?> requestedLookupClass) {
requestedLookupClass.getClass(); // null check
......@@ -325,11 +434,12 @@ public class MethodHandles {
}
/**
* Display the name of the class from which lookups are to be made.
* Displays the name of the class from which lookups are to be made.
* (The name is the one reported by {@link java.lang.Class#getName() Class.getName}.)
* If there are restrictions on the access permitted to this lookup,
* this is indicated by adding a suffix to the class name, consisting
* of a slash and a keyword. The keyword is chosen as follows:
* of a slash and a keyword. The keyword represents the strongest
* allowed access, and is chosen as follows:
* <ul>
* <li>If no access is allowed, the suffix is "/noaccess".
* <li>If only public access is allowed, the suffix is "/public".
......@@ -340,26 +450,37 @@ public class MethodHandles {
* access (public, package, private, and protected) is allowed.
* In this case, no suffix is added.
* This is true only of an object obtained originally from
* {@link java.dyn.MethodHandles#lookup() MethodHandles.lookup}.
* Objects created by {@link java.dyn.MethodHandles.Lookup#in() Lookup#in}
* {@link java.dyn.MethodHandles#lookup MethodHandles.lookup}.
* Objects created by {@link java.dyn.MethodHandles.Lookup#in Lookup.in}
* always have restricted access, and will display a suffix.
* <p>
* (It may seem strange that protected access should be
* stronger than private access. Viewed independently from
* package access, protected access is the first to be lost,
* because it requires a direct subclass relationship between
* caller and callee.)
* @see #in
*/
@Override
public String toString() {
String cname = lookupClass.getName();
switch (allowedModes) {
case TRUSTED:
return "/trusted"; // internal only
case 0: // no privileges
return cname + "/noaccess";
case PUBLIC:
return cname + "/public";
case PUBLIC|PACKAGE:
return cname + "/package";
case 0: // no privileges
return cname + "/noaccess";
case ALL_MODES & ~PROTECTED:
return cname + "/private";
case ALL_MODES:
return cname;
default:
return cname + "/private";
case TRUSTED:
return "/trusted"; // internal only; not exported
default: // Should not happen, but it's a bitfield...
cname = cname + "/" + Integer.toHexString(allowedModes);
assert(false) : cname;
return cname;
}
}
......@@ -374,11 +495,11 @@ public class MethodHandles {
}
/**
* Produce a method handle for a static method.
* Produces a method handle for a static method.
* The type of the method handle will be that of the method.
* (Since static methods do not take receivers, there is no
* additional receiver argument inserted into the method handle type,
* as there would be with {@link #findVirtual} or {@link #findSpecial}.)
* as there would be with {@link #findVirtual findVirtual} or {@link #findSpecial findSpecial}.)
* The method and all its argument types must be accessible to the lookup class.
* If the method's class has not yet been initialized, that is done
* immediately, before the method handle is returned.
......@@ -400,7 +521,7 @@ public class MethodHandles {
}
/**
* Produce a method handle for a virtual method.
* Produces a method handle for a virtual method.
* The type of the method handle will be that of the method,
* with the receiver type (usually {@code refc}) prepended.
* The method and all its argument types must be accessible to the lookup class.
......@@ -414,6 +535,16 @@ public class MethodHandles {
* The returned method handle will have
* {@linkplain MethodHandle#asVarargsCollector variable arity} if and only if
* the method's variable arity modifier bit ({@code 0x0080}) is set.
* <p>
* Because of the general equivalence between {@code invokevirtual}
* instructions and method handles produced by {@code findVirtual},
* if the class is {@code MethodHandle} and the name string is
* {@code invokeExact} or {@code invokeGeneric}, the resulting
* method handle is equivalent to one produced by
* {@link java.dyn.MethodHandles#exactInvoker MethodHandles.exactInvoker} or
* {@link java.dyn.MethodHandles#genericInvoker MethodHandles.genericInvoker}
* with the same {@code type} argument.
*
* @param refc the class or interface from which the method is accessed
* @param name the name of the method
* @param type the type of the method, with the receiver argument omitted
......@@ -428,7 +559,7 @@ public class MethodHandles {
}
/**
* Produce a method handle which creates an object and initializes it, using
* Produces a method handle which creates an object and initializes it, using
* the constructor of the specified type.
* The parameter types of the method handle will be those of the constructor,
* while the return type will be a reference to the constructor's class.
......@@ -437,7 +568,7 @@ public class MethodHandles {
* immediately, before the method handle is returned.
* <p>
* Note: The requested type must have a return type of {@code void}.
* This is consistent with the JVM's treatment of constructor signatures.
* This is consistent with the JVM's treatment of constructor type descriptors.
* <p>
* The returned method handle will have
* {@linkplain MethodHandle#asVarargsCollector variable arity} if and only if
......@@ -473,7 +604,7 @@ public class MethodHandles {
}
/**
* Produce an early-bound method handle for a virtual method,
* Produces an early-bound method handle for a virtual method,
* as if called from an {@code invokespecial}
* instruction from {@code caller}.
* The type of the method handle will be that of the method,
......@@ -510,12 +641,13 @@ public class MethodHandles {
}
/**
* Produce a method handle giving read access to a non-static field.
* Produces a method handle giving read access to a non-static field.
* The type of the method handle will have a return type of the field's
* value type.
* The method handle's single argument will be the instance containing
* the field.
* Access checking is performed immediately on behalf of the lookup class.
* @param refc the class or interface from which the method is accessed
* @param name the field's name
* @param type the field's type
* @return a method handle which can load values from the field
......@@ -526,12 +658,13 @@ public class MethodHandles {
}
/**
* Produce a method handle giving write access to a non-static field.
* Produces a method handle giving write access to a non-static field.
* The type of the method handle will have a void return type.
* The method handle will take two arguments, the instance containing
* the field, and the value to be stored.
* The second argument will be of the field's value type.
* Access checking is performed immediately on behalf of the lookup class.
* @param refc the class or interface from which the method is accessed
* @param name the field's name
* @param type the field's type
* @return a method handle which can store values into the field
......@@ -542,11 +675,12 @@ public class MethodHandles {
}
/**
* Produce a method handle giving read access to a static field.
* Produces a method handle giving read access to a static field.
* The type of the method handle will have a return type of the field's
* value type.
* The method handle will take no arguments.
* Access checking is performed immediately on behalf of the lookup class.
* @param refc the class or interface from which the method is accessed
* @param name the field's name
* @param type the field's type
* @return a method handle which can load values from the field
......@@ -557,11 +691,12 @@ public class MethodHandles {
}
/**
* Produce a method handle giving write access to a static field.
* Produces a method handle giving write access to a static field.
* The type of the method handle will have a void return type.
* The method handle will take a single
* argument, of the field's value type, the value to be stored.
* Access checking is performed immediately on behalf of the lookup class.
* @param refc the class or interface from which the method is accessed
* @param name the field's name
* @param type the field's type
* @return a method handle which can store values into the field
......@@ -572,7 +707,7 @@ public class MethodHandles {
}
/**
* Produce an early-bound method handle for a non-static method.
* Produces an early-bound method handle for a non-static method.
* The receiver must have a supertype {@code defc} in which a method
* of the given name and type is accessible to the lookup class.
* The method and all its argument types must be accessible to the lookup class.
......@@ -649,7 +784,7 @@ return mh1;
}
/**
* Produce a method handle for a reflected method.
* Produces a method handle for a reflected method.
* It will bypass checks for overriding methods on the receiver,
* as if by a {@code invokespecial} instruction from within the {@code specialCaller}.
* The type of the method handle will be that of the method,
......@@ -677,7 +812,7 @@ return mh1;
}
/**
* Produce a method handle for a reflected constructor.
* Produces a method handle for a reflected constructor.
* The type of the method handle will be that of the constructor,
* with the return type changed to the declaring class.
* The method handle will perform a {@code newInstance} operation,
......@@ -704,7 +839,7 @@ return mh1;
}
/**
* Produce a method handle giving read access to a reflected field.
* Produces a method handle giving read access to a reflected field.
* The type of the method handle will have a return type of the field's
* value type.
* If the field is static, the method handle will take no arguments.
......@@ -721,7 +856,7 @@ return mh1;
}
/**
* Produce a method handle giving write access to a reflected field.
* Produces a method handle giving write access to a reflected field.
* The type of the method handle will have a void return type.
* If the field is static, the method handle will take a single
* argument, of the field's value type, the value to be stored.
......@@ -875,12 +1010,13 @@ return mh1;
}
/**
* Produce a method handle giving read access to elements of an array.
* Produces a method handle giving read access to elements of an array.
* The type of the method handle will have a return type of the array's
* element type. Its first argument will be the array type,
* and the second will be {@code int}.
* @param arrayClass an array type
* @return a method handle which can load values from the given array type
* @throws NullPointerException if the argument is null
* @throws IllegalArgumentException if arrayClass is not an array type
*/
public static
......@@ -889,11 +1025,12 @@ return mh1;
}
/**
* Produce a method handle giving write access to elements of an array.
* Produces a method handle giving write access to elements of an array.
* The type of the method handle will have a void return type.
* Its last argument will be the array's element type.
* The first and second arguments will be the array type and int.
* @return a method handle which can store values into the array type
* @throws NullPointerException if the argument is null
* @throws IllegalArgumentException if arrayClass is not an array type
*/
public static
......@@ -904,47 +1041,7 @@ return mh1;
/// method handle invocation (reflective style)
/**
* Produce a method handle which will invoke any method handle of the
* given type on a standard set of {@code Object} type arguments.
* The resulting invoker will be a method handle with the following
* arguments:
* <ul>
* <li>a single {@code MethodHandle} target
* <li>zero or more {@code Object} values (one for each argument in {@code type})
* </ul>
* <p>
* The invoker will behave like a call to {@link MethodHandle.invokeGeneric} with
* the indicated {@code type}.
* That is, if the target is exactly of the given {@code type}, it will behave
* like {@code invokeExact}; otherwise it behave as if {@link MethodHandle.asType}
* is used to convert the target to the required {@code type}.
* <p>
* The type of the returned invoker will not be the given {@code type}, but rather
* will have all parameter and return types replaced by {@code Object}.
* <p>
* Before invoking its target, the invoker will apply reference casts as
* necessary and unbox and widen primitive arguments, as if by {@link #convertArguments}.
* The return value of the invoker will be an {@code Object} reference,
* boxing a primitive value if the original type returns a primitive,
* and always null if the original type returns void.
* <p>
* This method is equivalent to the following code (though it may be more efficient):
* <p><blockquote><pre>
* MethodHandle invoker = lookup().findVirtual(MethodHandle.class, "invokeGeneric", type);
* MethodType genericType = type.generic();
* genericType = genericType.insertParameterType(0, MethodHandle.class);
* return invoker.asType(genericType);
* </pre></blockquote>
* @param type the type of target methods which the invoker will apply to
* @return a method handle suitable for invoking any method handle of the given type
*/
static public
MethodHandle genericInvoker(MethodType type) {
return invokers(type).genericInvoker();
}
/**
* Produce a method handle which will invoke any method handle of the
* Produces a method handle which will invoke any method handle of the
* given {@code type} on a standard set of {@code Object} type arguments
* and a single trailing {@code Object[]} array.
* The resulting invoker will be a method handle with the following
......@@ -955,10 +1052,10 @@ return mh1;
* <li>an {@code Object[]} array containing more arguments
* </ul>
* <p>
* The invoker will behave like a call to {@link MethodHandle.invokeGeneric} with
* The invoker will behave like a call to {@link MethodHandle#invokeGeneric invokeGeneric} with
* the indicated {@code type}.
* That is, if the target is exactly of the given {@code type}, it will behave
* like {@code invokeExact}; otherwise it behave as if {@link MethodHandle.asType}
* like {@code invokeExact}; otherwise it behave as if {@link MethodHandle#asType asType}
* is used to convert the target to the required {@code type}.
* <p>
* The type of the returned invoker will not be the given {@code type}, but rather
......@@ -973,12 +1070,13 @@ return mh1;
* <p>
* This method is equivalent to the following code (though it may be more efficient):
* <p><blockquote><pre>
MethodHandle invoker = publicLookup()
.findVirtual(MethodHandle.class, "invokeGeneric", type)
MethodHandle invoker = MethodHandles.genericInvoker(type);
int spreadArgCount = type.parameterCount - objectArgCount;
invoker = invoker.asSpreader(Object[].class, spreadArgCount);
return invoker;
* </pre></blockquote>
* <p>
* This method throws no reflective or security exceptions.
* @param type the desired target type
* @param objectArgCount number of fixed (non-varargs) {@code Object} arguments
* @return a method handle suitable for invoking any method handle of the given type
......@@ -991,15 +1089,37 @@ return invoker;
}
/**
* Produce a method handle which will take a invoke any method handle of the
* given type. The resulting invoker will have a type which is
* Produces a special <em>invoker method handle</em> which can be used to
* invoke any method handle of the given type, as if by {@code invokeExact}.
* The resulting invoker will have a type which is
* exactly equal to the desired type, except that it will accept
* an additional leading argument of type {@code MethodHandle}.
* <p>
* This method is equivalent to the following code (though it may be more efficient):
* <p><blockquote><pre>
* lookup().findVirtual(MethodHandle.class, "invokeExact", type);
publicLookup().findVirtual(MethodHandle.class, "invokeExact", type)
* </pre></blockquote>
*
* <p style="font-size:smaller;">
* <em>Discussion:</em>
* Invoker method handles can be useful when working with variable method handles
* of unknown types.
* For example, to emulate an {@code invokeExact} call to a variable method
* handle {@code M}, extract its type {@code T},
* look up the invoker method {@code X} for {@code T},
* and call the invoker method, as {@code X.invokeGeneric(T, A...)}.
* (It would not work to call {@code X.invokeExact}, since the type {@code T}
* is unknown.)
* If spreading, collecting, or other argument transformations are required,
* they can be applied once to the invoker {@code X} and reused on many {@code M}
* method handle values, as long as they are compatible with the type of {@code X}.
* <p>
* <em>(Note: The invoker method is not available via the Core Reflection API.
* An attempt to call {@linkplain java.lang.reflect.Method#invoke Method.invoke}
* on the declared {@code invokeExact} or {@code invokeGeneric} method will raise an
* {@link java.lang.UnsupportedOperationException UnsupportedOperationException}.)</em>
* <p>
* This method throws no reflective or security exceptions.
* @param type the desired target type
* @return a method handle suitable for invoking any method handle of the given type
*/
......@@ -1008,12 +1128,38 @@ return invoker;
return invokers(type).exactInvoker();
}
/**
* Produces a special <em>invoker method handle</em> which can be used to
* invoke any method handle of the given type, as if by {@code invokeGeneric}.
* The resulting invoker will have a type which is
* exactly equal to the desired type, except that it will accept
* an additional leading argument of type {@code MethodHandle}.
* <p>
* Before invoking its target, the invoker will apply reference casts as
* necessary and unbox and widen primitive arguments, as if by {@link #convertArguments convertArguments}.
* The return value of the invoker will be an {@code Object} reference,
* boxing a primitive value if the original type returns a primitive,
* and always null if the original type returns void.
* <p>
* This method is equivalent to the following code (though it may be more efficient):
* <p><blockquote><pre>
publicLookup().findVirtual(MethodHandle.class, "invokeGeneric", type)
* </pre></blockquote>
* <p>
* This method throws no reflective or security exceptions.
* @param type the desired target type
* @return a method handle suitable for invoking any method handle convertible to the given type
*/
static public
MethodHandle genericInvoker(MethodType type) {
return invokers(type).genericInvoker();
}
static Invokers invokers(MethodType type) {
return MethodTypeImpl.invokers(IMPL_TOKEN, type);
}
/**
* <em>WORK IN PROGRESS:</em>
* Perform value checking, exactly as if for an adapted method handle.
* It is assumed that the given value is either null, of type T0,
* or (if T0 is primitive) of the wrapper type corresponding to T0.
......@@ -1084,7 +1230,7 @@ return invoker;
/// method handle modification (creation from other method handles)
/**
* Produce a method handle which adapts the type of the
* Produces a method handle which adapts the type of the
* given method handle to a new type by pairwise argument conversion.
* The original type and new type must have the same number of arguments.
* The resulting method handle is guaranteed to report a type
......@@ -1123,6 +1269,7 @@ return invoker;
* @return a method handle which delegates to {@code target} after performing
* any necessary argument conversions, and arranges for any
* necessary return value conversions
* @throws NullPointerException if either argument is null
* @throws WrongMethodTypeException if the conversion cannot be made
* @see MethodHandle#asType
* @see MethodHandles#explicitCastArguments
......@@ -1144,7 +1291,7 @@ return invoker;
}
/**
* Produce a method handle which adapts the type of the
* Produces a method handle which adapts the type of the
* given method handle to a new type by pairwise argument conversion.
* The original type and new type must have the same number of arguments.
* The resulting method handle is guaranteed to report a type
......@@ -1176,6 +1323,7 @@ return invoker;
* @return a method handle which delegates to {@code target} after performing
* any necessary argument conversions, and arranges for any
* necessary return value conversions
* @throws NullPointerException if either argument is null
* @throws WrongMethodTypeException if the conversion cannot be made
* @see MethodHandle#asType
* @see MethodHandles#convertArguments
......@@ -1223,7 +1371,7 @@ return invoker;
*/
/**
* Produce a method handle which adapts the calling sequence of the
* Produces a method handle which adapts the calling sequence of the
* given method handle to a new type, by reordering the arguments.
* The resulting method handle is guaranteed to report a type
* which is equal to the desired new type.
......@@ -1271,6 +1419,7 @@ assert((int)twice.invokeExact(21) == 42);
* @param reorder a string which controls the reordering
* @return a method handle which delegates to {@code target} after it
* drops unused arguments and moves and/or duplicates the other arguments
* @throws NullPointerException if any argument is null
*/
public static
MethodHandle permuteArguments(MethodHandle target, MethodType newType, int... reorder) {
......@@ -1296,11 +1445,10 @@ assert((int)twice.invokeExact(21) == 42);
}
/**
* <em>METHOD WILL BE REMOVED FOR PFD:</em>
* Equivalent to the following code:
* <p><blockquote><pre>
* int spreadPos = newType.parameterCount() - 1;
* Class<?> spreadType = newType.parameterType(spreadPos);
* Class&lt;?&gt; spreadType = newType.parameterType(spreadPos);
* int spreadCount = target.type().parameterCount() - spreadPos;
* MethodHandle adapter = target.asSpreader(spreadType, spreadCount);
* adapter = adapter.asType(newType);
......@@ -1310,9 +1458,8 @@ assert((int)twice.invokeExact(21) == 42);
* @param newType the expected type of the new method handle
* @return a method handle which spreads its final argument,
* before calling the original method handle
* @deprecated Use {@link MethodHandle#asSpreader}
*/
public static
/*non-public*/ static
MethodHandle spreadArguments(MethodHandle target, MethodType newType) {
MethodType oldType = target.type();
int inargs = newType.parameterCount();
......@@ -1330,11 +1477,10 @@ assert((int)twice.invokeExact(21) == 42);
}
/**
* <em>METHOD WILL BE REMOVED FOR PFD:</em>
* Equivalent to the following code:
* <p><blockquote><pre>
* int collectPos = target.type().parameterCount() - 1;
* Class<?> collectType = target.type().parameterType(collectPos);
* Class&lt;?&gt; collectType = target.type().parameterType(collectPos);
* if (!collectType.isArray()) collectType = Object[].class;
* int collectCount = newType.parameterCount() - collectPos;
* MethodHandle adapter = target.asCollector(collectType, collectCount);
......@@ -1345,9 +1491,8 @@ assert((int)twice.invokeExact(21) == 42);
* @param newType the expected type of the new method handle
* @return a method handle which collects some trailing argument
* into an array, before calling the original method handle
* @deprecated Use {@link MethodHandle#asCollector} instead.
*/
public static
/*non-public*/ static
MethodHandle collectArguments(MethodHandle target, MethodType newType) {
MethodType oldType = target.type();
int inargs = newType.parameterCount();
......@@ -1364,7 +1509,7 @@ assert((int)twice.invokeExact(21) == 42);
}
/**
* Produce a method handle of the requested return type which returns the given
* Produces a method handle of the requested return type which returns the given
* constant value every time it is invoked.
* <p>
* Before the method handle is returned, the passed-in value is converted to the requested type.
......@@ -1375,12 +1520,15 @@ assert((int)twice.invokeExact(21) == 42);
* @param type the return type of the desired method handle
* @param value the value to return
* @return a method handle of the given return type and no arguments, which always returns the given value
* @throws WrongMethodTypeException if the value cannot be converted to the required return type
* @throws NullPointerException if the {@code type} argument is null
* @throws ClassCastException if the value cannot be converted to the required return type
* @throws IllegalArgumentException if the given type is {@code void.class}
*/
public static
MethodHandle constant(Class<?> type, Object value) {
if (type.isPrimitive()) {
if (type == void.class) return identity(type);
if (type == void.class)
throw newIllegalArgumentException("void type");
Wrapper w = Wrapper.forPrimitiveType(type);
return identity(type).bindTo(w.convert(value, type));
} else {
......@@ -1389,64 +1537,22 @@ assert((int)twice.invokeExact(21) == 42);
}
/**
* Produce a method handle of the requested type which returns the given
* constant value every time it is invoked.
* <p>
* Before the method handle is returned, the passed-in value is converted to the requested return type,
* as if by {@link #explicitCastArguments #explicitCastArguments}.
* That is, if the return type is primitive, the value is unboxed,
* and the primitive value is widened and/or narrowed.
* Otherwise, reference conversions are attempted.
* @param type the type of the desired method handle
* @param value the value to return
* @return a method handle of the given return type and no arguments, which always returns the given value
* @throws WrongMethodTypeException if the value cannot be converted to the required return type
* Produces a method handle which returns its sole argument when invoked.
* <p>The identity function for {@code void} takes no arguments and returns no values.
* @param type the type of the sole parameter and return value of the desired method handle
* @return a unary method handle which accepts and returns the given type
* @throws NullPointerException if the argument is null
* @throws IllegalArgumentException if the given type is {@code void.class}
*/
public static
MethodHandle constant(MethodType type, Object value) {
MethodHandle target = constant(type.returnType(), value);
int len = type.parameterCount();
if (len == 0)
return target.asType(type);
target = target.asType(type.dropParameterTypes(0, len));
return dropArguments(target, 0, type.parameterList().subList(0, len));
}
/**
* Produce a method handle which returns its sole argument when invoked.
* <p>The identity function for {@code void} takes no arguments and returns no values.
* @param type the type of the sole parameter and return value of the desired method handle
* @return a unary method handle which accepts and returns the given type
*/
public static
MethodHandle identity(Class<?> type) {
if (type == void.class)
throw newIllegalArgumentException("void type");
return ValueConversions.identity(type);
}
/**
* Produce a method handle of the requested type which returns its argument when invoked.
* If the return type differs from the first argument type, the argument will be
* converted as if by {@link #explicitCastArguments explicitCastArguments}.
* If there are additional arguments beyond the first, they are discarded.
* <p>The identity function for {@code void} discards all its arguments.
* @param type the type of the desired method handle
* @return a method handle of the given type, which always returns its first argument
* @throws WrongMethodTypeException if the first argument cannot be converted to the required return type
*/
public static
MethodHandle identity(MethodType type) {
MethodHandle target = identity(type.returnType());
int len = type.parameterCount();
if (len == 1)
return explicitCastArguments(target, type);
if (len == 0)
throw new IllegalArgumentException("not enough arguments");
target = explicitCastArguments(target, type.dropParameterTypes(1, len));
return dropArguments(target, 1, type.parameterList().subList(1, len));
}
/**
* Produce a method handle which calls the original method handle {@code target},
* Produces a method handle which calls the original method handle {@code target},
* after inserting the given argument(s) at the given position.
* The formal parameters to {@code target} which will be supplied by those
* arguments are called <em>bound parameters</em>, because the new method
......@@ -1467,6 +1573,7 @@ assert((int)twice.invokeExact(21) == 42);
* @param values the series of arguments to insert
* @return a method handle which inserts an additional argument,
* before calling the original method handle
* @throws NullPointerException if the {@code target} argument or the {@code values} array is null
* @see MethodHandle#bindTo
*/
public static
......@@ -1501,7 +1608,7 @@ assert((int)twice.invokeExact(21) == 42);
}
/**
* Produce a method handle which calls the original method handle,
* Produces a method handle which calls the original method handle,
* after dropping the given argument(s) at the given position.
* The type of the new method handle will insert the given argument
* type(s), at that position, into the original handle's type.
......@@ -1533,6 +1640,9 @@ assertEquals("xz", (String) d12.invokeExact("x", 12, true, "z"));
* @param pos position of first argument to drop (zero for the leftmost)
* @return a method handle which drops arguments of the given types,
* before calling the original method handle
* @throws NullPointerException if the {@code target} argument is null,
* or if the {@code valueTypes} list or any of its elements is null
* @throws IllegalArgumentException if any of the {@code valueTypes} is {@code void.class}
*/
public static
MethodHandle dropArguments(MethodHandle target, int pos, List<Class<?>> valueTypes) {
......@@ -1550,7 +1660,7 @@ assertEquals("xz", (String) d12.invokeExact("x", 12, true, "z"));
}
/**
* Produce a method handle which calls the original method handle,
* Produces a method handle which calls the original method handle,
* after dropping the given argument(s) at the given position.
* The type of the new method handle will insert the given argument
* type(s), at that position, into the original handle's type.
......@@ -1563,6 +1673,9 @@ assertEquals("xz", (String) d12.invokeExact("x", 12, true, "z"));
* @param pos position of first argument to drop (zero for the leftmost)
* @return a method handle which drops arguments of the given types,
* before calling the original method handle
* @throws NullPointerException if the {@code target} argument is null,
* or if the {@code valueTypes} array or any of its elements is null
* @throws IllegalArgumentException if any of the {@code valueTypes} is {@code void.class}
*/
public static
MethodHandle dropArguments(MethodHandle target, int pos, Class<?>... valueTypes) {
......@@ -1577,7 +1690,8 @@ assertEquals("xz", (String) d12.invokeExact("x", 12, true, "z"));
* <p>
* The pre-processing is performed by one or more method handles,
* specified in the elements of the {@code filters} array.
* (If there are no elements in the array, the original target is returned.)
* Null arguments in the array are ignored, and the corresponding arguments left unchanged.
* (If there are no non-null elements in the array, the original target is returned.)
* Each filter is applied to the corresponding argument of the adapter.
* <p>
* If a filter {@code F} applies to the {@code N}th argument of
......@@ -1607,12 +1721,16 @@ assertEquals("xY", (String) f1.invokeExact("x", "y")); // xY
MethodHandle f2 = filterArguments(cat, 0, upcase, upcase);
assertEquals("XY", (String) f2.invokeExact("x", "y")); // XY
* </pre></blockquote>
*
* @param target the method handle to invoke after arguments are filtered
* @param pos the position of the first argument to filter
* @param filters method handles to call initially on filtered arguments
* @return method handle which incorporates the specified argument filtering logic
* @throws IllegalArgumentException if an element of {@code filters} is null or
* does not match a corresponding argument type of {@code target} as described above
* @throws NullPointerException if the {@code target} argument is null
* or if the {@code filters} array is null
* @throws IllegalArgumentException if a non-null element of {@code filters}
* does not match a corresponding argument type of {@code target} as described above,
* or if the {@code pos+filters.length} is greater than {@code target.type().parameterCount()}
*/
public static
MethodHandle filterArguments(MethodHandle target, int pos, MethodHandle... filters) {
......@@ -1620,17 +1738,18 @@ assertEquals("XY", (String) f2.invokeExact("x", "y")); // XY
MethodHandle adapter = target;
MethodType adapterType = targetType;
int maxPos = targetType.parameterCount();
int curPos = pos;
if (pos + filters.length > maxPos)
throw newIllegalArgumentException("too many filters");
int curPos = pos-1; // pre-incremented
for (MethodHandle filter : filters) {
if (curPos >= maxPos)
throw newIllegalArgumentException("too many filters");
curPos += 1;
if (filter == null) continue; // ignore null elements of filters
MethodType filterType = filter.type();
if (filterType.parameterCount() != 1
|| filterType.returnType() != targetType.parameterType(curPos))
throw newIllegalArgumentException("target and filter types do not match");
adapterType = adapterType.changeParameterType(curPos, filterType.parameterType(0));
adapter = MethodHandleImpl.filterArgument(IMPL_TOKEN, adapter, curPos, filter);
curPos += 1;
}
MethodType midType = adapter.type();
if (midType != adapterType)
......@@ -1665,7 +1784,8 @@ System.out.println((int) f0.invokeExact("x", "y")); // 2
* @param target the method handle to invoke before filtering the return value
* @param filter method handle to call on the return value
* @return method handle which incorporates the specified return value filtering logic
* @throws IllegalArgumentException if {@code filter} is null or
* @throws NullPointerException if either argument is null
* @throws IllegalArgumentException if {@code filter}
* does not match the return type of {@code target} as described above
*/
public static
......@@ -1675,9 +1795,11 @@ System.out.println((int) f0.invokeExact("x", "y")); // 2
if (filterType.parameterCount() != 1
|| filterType.parameterType(0) != targetType.returnType())
throw newIllegalArgumentException("target and filter types do not match");
// result = fold( lambda(retval, arg...) { filter(retval) },
// lambda( arg...) { target(arg...) } )
// FIXME: Too many nodes here.
MethodHandle returner = dropArguments(filter, 0, targetType.parameterList());
return foldArguments(returner, exactInvoker(target.type()).bindTo(target));
MethodHandle returner = dropArguments(filter, 1, targetType.parameterList());
return foldArguments(returner, target);
}
/**
......@@ -1700,7 +1822,7 @@ System.out.println((int) f0.invokeExact("x", "y")); // 2
* (Note that {@link #dropArguments(MethodHandle,int,List) dropArguments} can be used to remove any arguments
* that either the {@code combiner} or {@code target} does not wish to receive.
* If some of the incoming arguments are destined only for the combiner,
* consider using {@link MethodHandle#asCollector} instead, since those
* consider using {@link MethodHandle#asCollector asCollector} instead, since those
* arguments will not need to be live on the stack on entry to the
* target.)
* <p>
......@@ -1719,6 +1841,7 @@ System.out.println((int) f0.invokeExact("x", "y")); // 2
* @param target the method handle to invoke after arguments are combined
* @param combiner method handle to call initially on the incoming arguments
* @return method handle which incorporates the specified argument folding logic
* @throws NullPointerException if either argument is null
* @throws IllegalArgumentException if the first argument type of
* {@code target} is not the same as {@code combiner}'s return type,
* or if the following argument types of {@code target}
......@@ -1767,6 +1890,7 @@ System.out.println((int) f0.invokeExact("x", "y")); // 2
* @param target method handle to call if test passes
* @param fallback method handle to call if test fails
* @return method handle which incorporates the specified if/then/else logic
* @throws NullPointerException if any argument is null
* @throws IllegalArgumentException if {@code test} does not return boolean,
* or if all three method types do not match (with the return
* type of {@code test} changed to match that of {@code target}).
......@@ -1835,6 +1959,7 @@ System.out.println((int) f0.invokeExact("x", "y")); // 2
* @param exType the type of exception which the handler will catch
* @param handler method handle to call if a matching exception is thrown
* @return method handle which incorporates the specified try/catch logic
* @throws NullPointerException if any argument is null
* @throws IllegalArgumentException if {@code handler} does not accept
* the given exception type, or if the method handle types do
* not match in their return types and their
......@@ -1865,12 +1990,14 @@ System.out.println((int) f0.invokeExact("x", "y")); // 2
}
/**
* Produce a method handle which will throw exceptions of the given {@code exType}.
* Produces a method handle which will throw exceptions of the given {@code exType}.
* The method handle will accept a single argument of {@code exType},
* and immediately throw it as an exception.
* The method type will nominally specify a return of {@code returnType}.
* The return type may be anything convenient: It doesn't matter to the
* method handle's behavior, since it will never return normally.
* @return method handle which can throw the given exceptions
* @throws NullPointerException if either argument is null
*/
public static
MethodHandle throwException(Class<?> returnType, Class<? extends Throwable> exType) {
......@@ -1878,11 +2005,22 @@ System.out.println((int) f0.invokeExact("x", "y")); // 2
}
/**
* <em>PROVISIONAL API, WORK IN PROGRESS:</em>
* Produce a wrapper instance of the given "SAM" interface which redirects
* Produces an instance of the given "SAM" interface which redirects
* its calls to the given method handle.
* <p>
* A SAM interface is an interface which declares a single abstract method.
* The type must be public. (No additional access checks are performed.)
* When determining the unique abstract method of a SAM interface,
* the public {@code Object} methods ({@code toString}, {@code equals}, {@code hashCode})
* are disregarded. For example, {@link java.util.Comparator} is a SAM interface,
* even though it re-declares the {@code Object.equals} method.
* Also, if the SAM interface has a supertype,
* the SAM interface may override an inherited method.
* Any such overrides are respected, and the method handle will be accessible
* by either the inherited method or the SAM method.
* In particular, a {@linkplain java.lang.reflect.Method#isBridge bridge method}
* may be created if the methods have different return types.
* <p>
* The type must be public. No additional access checks are performed.
* <p>
* The resulting instance of the required SAM type will respond to
* invocation of the SAM type's single abstract method by calling
......@@ -1894,6 +2032,17 @@ System.out.println((int) f0.invokeExact("x", "y")); // 2
* instance is created, as if by a call to {@code asType},
* which may result in a {@code WrongMethodTypeException}.
* <p>
* The wrapper instance will implement the requested SAM interface
* and its super-types, but no other SAM types.
* This means that the SAM instance will not unexpectedly
* pass an {@code instanceof} test for any unrequested type.
* <p style="font-size:smaller;">
* <em>Implementation Note:</em>
* Therefore, each SAM instance must implement a unique SAM type.
* Implementations may not bundle together
* multiple SAM types onto single implementation classes
* in the style of {@link java.awt.AWTEventMulticaster}.
* <p>
* The method handle may throw an <em>undeclared exception</em>,
* which means any checked exception (or other checked throwable)
* not declared by the SAM type's single abstract method.
......@@ -1901,56 +2050,46 @@ System.out.println((int) f0.invokeExact("x", "y")); // 2
* {@link java.lang.reflect.UndeclaredThrowableException UndeclaredThrowableException}
* and thrown in that wrapped form.
* <p>
* The wrapper instance is guaranteed to be of a non-public
* implementation class C in a package containing no classes
* or methods except system-defined classes and methods.
* The implementation class C will have no public supertypes
* or public methods beyond the following:
* <ul>
* <li>the SAM type itself and any methods in the SAM type
* <li>the supertypes of the SAM type (if any) and their methods
* <li>{@link Object} and its methods
* <li>{@link java.dyn.AsInstanceObject AsInstanceObject} and its methods</li>
* </ul>
* <p>
* (Note: When determining the unique abstract method of a SAM interface,
* the public {@code Object} methods ({@code toString}, {@code equals}, {@code hashCode})
* are disregarded. For example, {@link java.util.Comparator} is a SAM interface,
* even though it re-declares the {@code Object.equals} method.)
* <p>
* No stable mapping is promised between the SAM type and
* the implementation class C. Over time, several implementation
* classes might be used for the same SAM type.
* <p>
* This method is not guaranteed to return a distinct
* wrapper object for each separate call. If the implementation is able
* to prove that a wrapper of the required SAM type
* has already been created for a given
* method handle, or for another method handle with the
* same behavior, the implementation may return that wrapper in place of
* a new wrapper.
* <p>
* This method is designed to apply to common use cases
* where a single method handle must interoperate with
* a type (class or interface) that implements a function-like
* API. Additional variations, such as SAM classes with
* private constructors, or interfaces with multiple but related
* entry points, must be covered by hand-written or automatically
* generated adapter classes. In those cases, consider implementing
* {@link java.dyn.MethodHandles.AsInstanceObject AsInstanceObject}
* in the adapters, so that generic code can extract the underlying
* method handle without knowing where the SAM adapter came from.
* Like {@link java.lang.Integer#valueOf Integer.valueOf},
* {@code asInstance} is a factory method whose results are defined
* by their behavior.
* It is not guaranteed to return a new instance for every call.
* <p>
* Future versions of this API may accept additional types,
* such as abstract classes with single abstract methods.
* Future versions of this API may also equip wrapper instances
* with one or more additional public "marker" interfaces.
*
* @param target the method handle to invoke from the wrapper
* @param samType the desired type of the wrapper, a SAM type
* @return a correctly-typed wrapper for the given {@code target}
* @throws NullPointerException if either argument is null
* @throws IllegalArgumentException if the {@code samType} is not a
* valid argument to this method
* @throws WrongMethodTypeException if the {@code target} cannot
* be converted to the type required by the SAM type
*/
// Other notes to implementors:
// <p>
// No stable mapping is promised between the SAM type and
// the implementation class C. Over time, several implementation
// classes might be used for the same SAM type.
// <p>
// If the implementation is able
// to prove that a wrapper of the required SAM type
// has already been created for a given
// method handle, or for another method handle with the
// same behavior, the implementation may return that wrapper in place of
// a new wrapper.
// <p>
// This method is designed to apply to common use cases
// where a single method handle must interoperate with
// an interface that implements a function-like
// API. Additional variations, such as SAM classes with
// private constructors, or interfaces with multiple but related
// entry points, must be covered by hand-written or automatically
// generated adapter classes.
//
public static
<T> T asInstance(final MethodHandle target, final Class<T> samType) {
// POC implementation only; violates the above contract several ways
......@@ -1963,15 +2102,15 @@ System.out.println((int) f0.invokeExact("x", "y")); // 2
final MethodHandle vaTarget = checkTarget.asSpreader(Object[].class, samMT.parameterCount());
return samType.cast(Proxy.newProxyInstance(
samType.getClassLoader(),
new Class[]{ samType, AsInstanceObject.class },
new Class[]{ samType, WrapperInstance.class },
new InvocationHandler() {
private Object getArg(String name) {
if ((Object)name == "getAsInstanceTarget") return target;
if ((Object)name == "getAsInstanceType") return samType;
if ((Object)name == "getWrapperInstanceTarget") return target;
if ((Object)name == "getWrapperInstanceType") return samType;
throw new AssertionError();
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
if (method.getDeclaringClass() == AsInstanceObject.class)
if (method.getDeclaringClass() == WrapperInstance.class)
return getArg(method.getName());
if (method.equals(sam))
return vaTarget.invokeExact(args);
......@@ -1983,21 +2122,49 @@ System.out.println((int) f0.invokeExact("x", "y")); // 2
}
/**
* <em>PROVISIONAL API, WORK IN PROGRESS:</em>
* Interface implemented by every object which is produced by {@link #asInstance asInstance}.
* The methods of this interface allow a caller to recover the parameters
* to {@code asInstance}.
* This allows applications to repeatedly convert between method handles
* and SAM objects, without the risk of creating unbounded delegation chains.
* Determine if the given object was produced by a call to {@link #asInstance asInstance}.
* @param x any reference
* @return true if the reference is not null and points to an object produced by {@code asInstance}
*/
public interface AsInstanceObject {
/** Produce or recover a target method handle which is behaviorally
* equivalent to the SAM method of this object.
*/
public MethodHandle getAsInstanceTarget();
/** Recover the SAM type for which this object was created.
*/
public Class<?> getAsInstanceType();
public static
boolean isWrapperInstance(Object x) {
return x instanceof WrapperInstance;
}
private static WrapperInstance asWrapperInstance(Object x) {
try {
if (x != null)
return (WrapperInstance) x;
} catch (ClassCastException ex) {
}
throw new IllegalArgumentException("not a wrapper instance");
}
/**
* Produces or recovers a target method handle which is behaviorally
* equivalent to the SAM method of this wrapper instance.
* The object {@code x} must have been produced by a call to {@link #asInstance asInstance}.
* This requirement may be tested via {@link #isWrapperInstance isWrapperInstance}.
* @param x any reference
* @return a method handle implementing the SAM method
* @throws IllegalArgumentException if the reference x is not to a wrapper instance
*/
public static
MethodHandle wrapperInstanceTarget(Object x) {
return asWrapperInstance(x).getWrapperInstanceTarget();
}
/**
* Recover the SAM type for which this wrapper instance was created.
* The object {@code x} must have been produced by a call to {@link #asInstance asInstance}.
* This requirement may be tested via {@link #isWrapperInstance isWrapperInstance}.
* @param x any reference
* @return the SAM type for which the wrapper was created
* @throws IllegalArgumentException if the reference x is not to a wrapper instance
*/
public static
Class<?> wrapperInstanceType(Object x) {
return asWrapperInstance(x).getWrapperInstanceType();
}
private static
......
jdk/src/share/classes/java/dyn/MethodType.java
浏览文件 @ d7393144
/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2008, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
......@@ -31,6 +31,7 @@ import java.util.HashMap;
import java.util.List;
import sun.dyn.Access;
import sun.dyn.Invokers;
import sun.dyn.MethodHandleImpl;
import sun.dyn.MethodTypeImpl;
import sun.dyn.util.BytecodeDescriptor;
import static sun.dyn.MemberName.newIllegalArgumentException;
......@@ -41,8 +42,8 @@ import static sun.dyn.MemberName.newIllegalArgumentException;
* and expected by a method handle caller. Method types must be properly
* matched between a method handle and all its callers,
* and the JVM's operations enforce this matching at, specifically
* during calls to {@link MethodHandle#invokeExact}
* and {@link MethodHandle#invokeGeneric}, and during execution
* during calls to {@link MethodHandle#invokeExact MethodHandle.invokeExact}
* and {@link MethodHandle#invokeGeneric MethodHandle.invokeGeneric}, and during execution
* of {@code invokedynamic} instructions.
* <p>
* The structure is a return type accompanied by any number of parameter types.
......@@ -70,8 +71,9 @@ import static sun.dyn.MemberName.newIllegalArgumentException;
* with the instructions in a class file's constant pool.
* <p>
* Like classes and strings, method types can also be represented directly
* in a class file's constant pool as constants. The may be loaded by an {@code ldc}
* instruction which refers to a suitable {@code CONSTANT_MethodType} constant pool entry.
* in a class file's constant pool as constants.
* A method type may be loaded by an {@code ldc} instruction which refers
* to a suitable {@code CONSTANT_MethodType} constant pool entry.
* The entry refers to a {@code CONSTANT_Utf8} spelling for the descriptor string.
* For more details, see the <a href="package-summary.html#mtcon">package summary</a>.
* <p>
......@@ -124,15 +126,32 @@ class MethodType {
this.ptypes = ptypes;
}
private void checkRtype(Class<?> rtype) {
private static void checkRtype(Class<?> rtype) {
rtype.equals(rtype); // null check
}
private void checkPtypes(Class<?>[] ptypes) {
private static int checkPtype(Class<?> ptype) {
ptype.getClass(); //NPE
if (ptype == void.class)
throw newIllegalArgumentException("parameter type cannot be void");
if (ptype == double.class || ptype == long.class) return 1;
return 0;
}
/** Return number of extra slots (count of long/double args). */
private static int checkPtypes(Class<?>[] ptypes) {
int slots = 0;
for (Class<?> ptype : ptypes) {
ptype.equals(ptype); // null check
if (ptype == void.class)
throw newIllegalArgumentException("parameter type cannot be void");
slots += checkPtype(ptype);
}
checkSlotCount(ptypes.length + slots);
return slots;
}
private static void checkSlotCount(int count) {
if ((count & 0xFF) != count)
throw newIllegalArgumentException("bad parameter count "+count);
}
private static IndexOutOfBoundsException newIndexOutOfBoundsException(Object num) {
if (num instanceof Integer) num = "bad index: "+num;
return new IndexOutOfBoundsException(num.toString());
}
static final HashMap<MethodType,MethodType> internTable
......@@ -140,27 +159,39 @@ class MethodType {
static final Class<?>[] NO_PTYPES = {};
/** Find or create an instance of the given method type.
/**
* Find or create an instance of the given method type.
* @param rtype the return type
* @param ptypes the parameter types
* @return a method type with the given parts
* @throws NullPointerException if rtype or any ptype is null
* @throws IllegalArgumentException if any of the ptypes is void
* @return a method type with the given components
* @throws NullPointerException if {@code rtype} or {@code ptypes} or any element of {@code ptypes} is null
* @throws IllegalArgumentException if any element of {@code ptypes} is {@code void.class}
*/
public static
MethodType methodType(Class<?> rtype, Class<?>[] ptypes) {
return makeImpl(rtype, ptypes, false);
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}. */
/**
* Finds or creates a method type with the given components.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* @return a method type with the given components
* @throws NullPointerException if {@code rtype} or {@code ptypes} or any element of {@code ptypes} is null
* @throws IllegalArgumentException if any element of {@code ptypes} is {@code void.class}
*/
public static
MethodType methodType(Class<?> rtype, List<? extends Class<?>> ptypes) {
MethodType methodType(Class<?> rtype, List<Class<?>> ptypes) {
boolean notrust = false; // random List impl. could return evil ptypes array
return makeImpl(rtype, ptypes.toArray(NO_PTYPES), notrust);
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
* The leading parameter type is prepended to the remaining array.
/**
* Finds or creates a method type with the given components.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* The leading parameter type is prepended to the remaining array.
* @return a method type with the given components
* @throws NullPointerException if {@code rtype} or {@code ptype0} or {@code ptypes} or any element of {@code ptypes} is null
* @throws IllegalArgumentException if {@code ptype0} or {@code ptypes} or any element of {@code ptypes} is {@code void.class}
*/
public static
MethodType methodType(Class<?> rtype, Class<?> ptype0, Class<?>... ptypes) {
......@@ -170,25 +201,37 @@ class MethodType {
return makeImpl(rtype, ptypes1, true);
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
* The resulting method has no parameter types.
/**
* Finds or creates a method type with the given components.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* The resulting method has no parameter types.
* @return a method type with the given return value
* @throws NullPointerException if {@code rtype} is null
*/
public static
MethodType methodType(Class<?> rtype) {
return makeImpl(rtype, NO_PTYPES, true);
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
* The resulting method has the single given parameter type.
/**
* Finds or creates a method type with the given components.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* The resulting method has the single given parameter type.
* @return a method type with the given return value and parameter type
* @throws NullPointerException if {@code rtype} or {@code ptype0} is null
* @throws IllegalArgumentException if {@code ptype0} is {@code void.class}
*/
public static
MethodType methodType(Class<?> rtype, Class<?> ptype0) {
return makeImpl(rtype, new Class<?>[]{ ptype0 }, true);
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
* The resulting method has the same parameter types as {@code ptypes},
* and the specified return type.
/**
* Finds or creates a method type with the given components.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* The resulting method has the same parameter types as {@code ptypes},
* and the specified return type.
* @throws NullPointerException if {@code rtype} or {@code ptypes} is null
*/
public static
MethodType methodType(Class<?> rtype, MethodType ptypes) {
......@@ -237,17 +280,20 @@ class MethodType {
private static final MethodType[] objectOnlyTypes = new MethodType[20];
/**
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
* Finds or creates a method type whose components are {@code Object} with an optional trailing {@code Object[]} array.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* All parameters and the return type will be {@code Object},
* except the final varargs parameter if any, which will be {@code Object[]}.
* @param objectArgCount number of parameters (excluding the varargs parameter if any)
* @param varargs whether there will be a varargs parameter, of type {@code Object[]}
* @return a totally generic method type, given only its count of parameters and varargs
* @throws IllegalArgumentException if {@code objectArgCount} is negative or greater than 255
* @see #genericMethodType(int)
*/
public static
MethodType genericMethodType(int objectArgCount, boolean varargs) {
MethodType mt;
checkSlotCount(objectArgCount);
int ivarargs = (!varargs ? 0 : 1);
int ootIndex = objectArgCount*2 + ivarargs;
if (ootIndex < objectOnlyTypes.length) {
......@@ -265,9 +311,12 @@ class MethodType {
}
/**
* Finds or creates a method type whose components are all {@code Object}.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* All parameters and the return type will be Object.
* @param objectArgCount number of parameters
* @return a totally generic method type, given only its count of parameters
* @throws IllegalArgumentException if {@code objectArgCount} is negative or greater than 255
* @see #genericMethodType(int, boolean)
*/
public static
......@@ -275,27 +324,41 @@ class MethodType {
return genericMethodType(objectArgCount, false);
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
/**
* Finds or creates a method type with a single different parameter type.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* @param num the index (zero-based) of the parameter type to change
* @param nptype a new parameter type to replace the old one with
* @return the same type, except with the selected parameter changed
* @throws IndexOutOfBoundsException if {@code num} is not a valid index into {@code parameterArray()}
* @throws IllegalArgumentException if {@code nptype} is {@code void.class}
* @throws NullPointerException if {@code nptype} is null
*/
public MethodType changeParameterType(int num, Class<?> nptype) {
if (parameterType(num) == nptype) return this;
checkPtype(nptype);
Class<?>[] nptypes = ptypes.clone();
nptypes[num] = nptype;
return makeImpl(rtype, nptypes, true);
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
/**
* Finds or creates a method type with additional parameter types.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* @param num the position (zero-based) of the inserted parameter type(s)
* @param ptypesToInsert zero or more a new parameter types to insert into the parameter list
* @param ptypesToInsert zero or more new parameter types to insert into the parameter list
* @return the same type, except with the selected parameter(s) inserted
* @throws IndexOutOfBoundsException if {@code num} is negative or greater than {@code parameterCount()}
* @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class}
* or if the resulting method type would have more than 255 parameter slots
* @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null
*/
public MethodType insertParameterTypes(int num, Class<?>... ptypesToInsert) {
int len = ptypes.length;
if (num < 0 || num > len)
throw newIllegalArgumentException("num="+num); //SPECME
throw newIndexOutOfBoundsException(num);
int ins = checkPtypes(ptypesToInsert);
checkSlotCount(parameterSlotCount() + ptypesToInsert.length + ins);
int ilen = ptypesToInsert.length;
if (ilen == 0) return this;
Class<?>[] nptypes = Arrays.copyOfRange(ptypes, 0, len+ilen);
......@@ -304,40 +367,61 @@ class MethodType {
return makeImpl(rtype, nptypes, true);
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
* @param ptypesToInsert zero or more a new parameter types to insert after the end of the parameter list
/**
* Finds or creates a method type with additional parameter types.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* @param ptypesToInsert zero or more new parameter types to insert after the end of the parameter list
* @return the same type, except with the selected parameter(s) appended
* @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class}
* or if the resulting method type would have more than 255 parameter slots
* @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null
*/
public MethodType appendParameterTypes(Class<?>... ptypesToInsert) {
return insertParameterTypes(parameterCount(), ptypesToInsert);
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
* @param ptypesToInsert zero or more a new parameter types to insert after the end of the parameter list
* @return the same type, except with the selected parameter(s) appended
*/
public MethodType appendParameterTypes(List<Class<?>> ptypesToInsert) {
return insertParameterTypes(parameterCount(), ptypesToInsert);
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
/**
* Finds or creates a method type with additional parameter types.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* @param num the position (zero-based) of the inserted parameter type(s)
* @param ptypesToInsert zero or more a new parameter types to insert into the parameter list
* @param ptypesToInsert zero or more new parameter types to insert into the parameter list
* @return the same type, except with the selected parameter(s) inserted
* @throws IndexOutOfBoundsException if {@code num} is negative or greater than {@code parameterCount()}
* @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class}
* or if the resulting method type would have more than 255 parameter slots
* @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null
*/
public MethodType insertParameterTypes(int num, List<Class<?>> ptypesToInsert) {
return insertParameterTypes(num, ptypesToInsert.toArray(NO_PTYPES));
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
/**
* Finds or creates a method type with additional parameter types.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* @param ptypesToInsert zero or more new parameter types to insert after the end of the parameter list
* @return the same type, except with the selected parameter(s) appended
* @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class}
* or if the resulting method type would have more than 255 parameter slots
* @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null
*/
public MethodType appendParameterTypes(List<Class<?>> ptypesToInsert) {
return insertParameterTypes(parameterCount(), ptypesToInsert);
}
/**
* Finds or creates a method type with some parameter types omitted.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* @param start the index (zero-based) of the first parameter type to remove
* @param end the index (greater than {@code start}) of the first parameter type after not to remove
* @return the same type, except with the selected parameter(s) removed
* @throws IndexOutOfBoundsException if {@code start} is negative or greater than {@code parameterCount()}
* or if {@code end} is negative or greater than {@code parameterCount()}
* or if {@code start} is greater than {@code end}
*/
public MethodType dropParameterTypes(int start, int end) {
int len = ptypes.length;
if (!(0 <= start && start <= end && end <= len))
throw newIllegalArgumentException("start="+start+" end="+end); //SPECME
throw newIndexOutOfBoundsException("start="+start+" end="+end);
if (start == end) return this;
Class<?>[] nptypes;
if (start == 0) {
......@@ -361,17 +445,20 @@ class MethodType {
return makeImpl(rtype, nptypes, true);
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
/**
* Finds or creates a method type with a different return type.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* @param nrtype a return parameter type to replace the old one with
* @return the same type, except with the return type change
* @throws NullPointerException if {@code nrtype} is null
*/
public MethodType changeReturnType(Class<?> nrtype) {
if (returnType() == nrtype) return this;
return makeImpl(nrtype, ptypes, true);
}
/** Convenience method.
* Report if this type contains a primitive argument or return value.
/**
* Reports if this type contains a primitive argument or return value.
* The return type {@code void} counts as a primitive.
* @return true if any of the types are primitives
*/
......@@ -379,8 +466,8 @@ class MethodType {
return form.hasPrimitives();
}
/** Convenience method.
* Report if this type contains a wrapper argument or return value.
/**
* Reports if this type contains a wrapper argument or return value.
* Wrappers are types which box primitive values, such as {@link Integer}.
* The reference type {@code java.lang.Void} counts as a wrapper.
* @return true if any of the types are wrappers
......@@ -389,8 +476,9 @@ class MethodType {
return unwrap() != this;
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
* Erase all reference types to {@code Object}.
/**
* Erases all reference types to {@code Object}.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* All primitive types (including {@code void}) will remain unchanged.
* @return a version of the original type with all reference types replaced
*/
......@@ -398,8 +486,9 @@ class MethodType {
return form.erasedType();
}
/** Convenience method for {@link #genericMethodType(int)}.
* Convert all types, both reference and primitive, to {@code Object}.
/**
* Converts all types, both reference and primitive, to {@code Object}.
* Convenience method for {@link #genericMethodType(int) genericMethodType}.
* The expression {@code type.wrap().erase()} produces the same value
* as {@code type.generic()}.
* @return a version of the original type with all types replaced
......@@ -408,8 +497,9 @@ class MethodType {
return genericMethodType(parameterCount());
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
* Convert all primitive types to their corresponding wrapper types.
/**
* Converts all primitive types to their corresponding wrapper types.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* All reference types (including wrapper types) will remain unchanged.
* A {@code void} return type is changed to the type {@code java.lang.Void}.
* The expression {@code type.wrap().erase()} produces the same value
......@@ -420,8 +510,9 @@ class MethodType {
return hasPrimitives() ? wrapWithPrims(this) : this;
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
/**
* Convert all wrapper types to their corresponding primitive types.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* All primitive types (including {@code void}) will remain unchanged.
* A return type of {@code java.lang.Void} is changed to {@code void}.
* @return a version of the original type with all wrapper types replaced
......@@ -456,23 +547,33 @@ class MethodType {
return uwt;
}
/** @param num the index (zero-based) of the desired parameter type
* @return the selected parameter type
/**
* Returns the parameter type at the specified index, within this method type.
* @param num the index (zero-based) of the desired parameter type
* @return the selected parameter type
* @throws IndexOutOfBoundsException if {@code num} is not a valid index into {@code parameterArray()}
*/
public Class<?> parameterType(int num) {
return ptypes[num];
}
/** @return the number of parameter types */
/**
* Returns the number of parameter types in this method type.
* @return the number of parameter types
*/
public int parameterCount() {
return ptypes.length;
}
/** @return the return type */
/**
* Returns the return type of this method type.
* @return the return type
*/
public Class<?> returnType() {
return rtype;
}
/**
* Convenience method to present the arguments as a list.
* Presents the parameter types as a list (a convenience method).
* The list will be immutable.
* @return the parameter types (as an immutable list)
*/
public List<Class<?>> parameterList() {
......@@ -480,7 +581,7 @@ class MethodType {
}
/**
* Convenience method to present the arguments as an array.
* Presents the parameter types as an array (a convenience method).
* Changes to the array will not result in changes to the type.
* @return the parameter types (as a fresh copy if necessary)
*/
......@@ -524,14 +625,14 @@ class MethodType {
}
/**
* Returns a string representation of the method type,
* of the form {@code "(PT0,PT1...)RT"}.
* The string representation of a method type is a
* parenthesis enclosed, comma separated list of type names,
* followed immediately by the return type.
* <p>
* Each type is represented by its
* {@link java.lang.Class#getSimpleName simple name}.
* If a type name name is array, it the base type followed
* by [], rather than the Class.getName of the array type.
*/
@Override
public String toString() {
......@@ -548,21 +649,22 @@ class MethodType {
/// Queries which have to do with the bytecode architecture
/** The number of JVM stack slots required to invoke a method
/** Reports the number of JVM stack slots required to invoke a method
* of this type. Note that (for historic reasons) the JVM requires
* a second stack slot to pass long and double arguments.
* So this method returns {@link #parameterCount()} plus the
* So this method returns {@link #parameterCount() parameterCount} plus the
* number of long and double parameters (if any).
* <p>
* This method is included for the benfit of applications that must
* generate bytecodes that process method handles and invokedynamic.
* @return the number of JVM stack slots for this type's parameters
* @deprecated Will be removed for PFD.
*/
public int parameterSlotCount() {
return form.parameterSlotCount();
}
/** Number of JVM stack slots which carry all parameters including and after
/** Reports the number of JVM stack slots which carry all parameters including and after
* the given position, which must be in the range of 0 to
* {@code parameterCount} inclusive. Successive parameters are
* more shallowly stacked, and parameters are indexed in the bytecodes
......@@ -583,6 +685,8 @@ class MethodType {
* @param num an index (zero-based, inclusive) within the parameter types
* @return the index of the (shallowest) JVM stack slot transmitting the
* given parameter
* @throws IllegalArgumentException if {@code num} is negative or greater than {@code parameterCount()}
* @deprecated Will be removed for PFD.
*/
public int parameterSlotDepth(int num) {
if (num < 0 || num > ptypes.length)
......@@ -590,7 +694,7 @@ class MethodType {
return form.parameterToArgSlot(num-1);
}
/** The number of JVM stack slots required to receive a return value
/** Reports the number of JVM stack slots required to receive a return value
* from a method of this type.
* If the {@link #returnType() return type} is void, it will be zero,
* else if the return type is long or double, it will be two, else one.
......@@ -598,13 +702,15 @@ class MethodType {
* This method is included for the benfit of applications that must
* generate bytecodes that process method handles and invokedynamic.
* @return the number of JVM stack slots (0, 1, or 2) for this type's return value
* @deprecated Will be removed for PFD.
*/
public int returnSlotCount() {
return form.returnSlotCount();
}
/** Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[])}.
* Find or create an instance of the given method type.
/**
* Find or create an instance of a method type, given the spelling of its bytecode descriptor.
* Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
* Any class or interface name embedded in the descriptor string
* will be resolved by calling {@link ClassLoader#loadClass(java.lang.String)}
* on the given loader (or if it is null, on the system class loader).
......@@ -614,10 +720,10 @@ class MethodType {
* not all reachable from a common class loader.
* <p>
* This method is included for the benfit of applications that must
* generate bytecodes that process method handles and invokedynamic.
* @param descriptor a bytecode-level signature string "(T...)T"
* generate bytecodes that process method handles and {@code invokedynamic}.
* @param descriptor a bytecode-level type descriptor string "(T...)T"
* @param loader the class loader in which to look up the types
* @return a method type matching the bytecode-level signature
* @return a method type matching the bytecode-level type descriptor
* @throws IllegalArgumentException if the string is not well-formed
* @throws TypeNotPresentException if a named type cannot be found
*/
......@@ -631,17 +737,17 @@ class MethodType {
}
/**
* Create a bytecode descriptor representation of the method type.
* Produces a bytecode descriptor representation of the method type.
* <p>
* Note that this is not a strict inverse of {@link #fromMethodDescriptorString}.
* Note that this is not a strict inverse of {@link #fromMethodDescriptorString fromMethodDescriptorString}.
* Two distinct classes which share a common name but have different class loaders
* will appear identical when viewed within descriptor strings.
* <p>
* This method is included for the benfit of applications that must
* generate bytecodes that process method handles and invokedynamic.
* {@link #fromMethodDescriptorString(java.lang.String, java.lang.ClassLoader)},
* generate bytecodes that process method handles and {@code invokedynamic}.
* {@link #fromMethodDescriptorString(java.lang.String, java.lang.ClassLoader) fromMethodDescriptorString},
* because the latter requires a suitable class loader argument.
* @return the bytecode signature representation
* @return the bytecode type descriptor representation
*/
public String toMethodDescriptorString() {
return BytecodeDescriptor.unparse(this);
......
jdk/src/share/classes/java/dyn/MutableCallSite.java
浏览文件 @ d7393144
/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2008, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
......@@ -73,7 +73,7 @@ assertEquals("Wilma, dear?", (String) worker2.invokeExact());
* (This is a normal consequence of the Java Memory Model as applied
* to object fields.)
* <p>
* The {@link #sync sync} operation provides a way to force threads
* The {@link #syncAll syncAll} operation provides a way to force threads
* to accept a new target value, even if there is no other synchronization.
* <p>
* For target values which will be frequently updated, consider using
......@@ -82,13 +82,17 @@ assertEquals("Wilma, dear?", (String) worker2.invokeExact());
*/
public class MutableCallSite extends CallSite {
/**
* Make a blank call site object with the given method type.
* An initial target method is supplied which will throw
* an {@link IllegalStateException} if called.
* Creates a blank call site object with the given method type.
* The initial target is set to a method handle of the given type
* which will throw an {@link IllegalStateException} if called.
* <p>
* The type of the call site is permanently set to the given type.
* <p>
* Before this {@code CallSite} object is returned from a bootstrap method,
* or invoked in some other manner,
* it is usually provided with a more useful target method,
* via a call to {@link CallSite#setTarget(MethodHandle) setTarget}.
* @param type the method type that this call site will have
* @throws NullPointerException if the proposed type is null
*/
public MutableCallSite(MethodType type) {
......@@ -96,8 +100,9 @@ public class MutableCallSite extends CallSite {
}
/**
* Make a blank call site object, possibly equipped with an initial target method handle.
* @param target the method handle which will be the initial target of the call site
* Creates a call site object with an initial target method handle.
* The type of the call site is permanently set to the initial target's type.
* @param target the method handle that will be the initial target of the call site
* @throws NullPointerException if the proposed target is null
*/
public MutableCallSite(MethodHandle target) {
......@@ -105,7 +110,59 @@ public class MutableCallSite extends CallSite {
}
/**
* Perform a synchronization operation on each call site in the given array,
* Returns the target method of the call site, which behaves
* like a normal field of the {@code MutableCallSite}.
* <p>
* The interactions of {@code getTarget} with memory are the same
* as of a read from an ordinary variable, such as an array element or a
* non-volatile, non-final field.
* <p>
* In particular, the current thread may choose to reuse the result
* of a previous read of the target from memory, and may fail to see
* a recent update to the target by another thread.
*
* @return the linkage state of this call site, a method handle which can change over time
* @see #setTarget
*/
@Override public final MethodHandle getTarget() {
return target;
}
/**
* Updates the target method of this call site, as a normal variable.
* The type of the new target must agree with the type of the old target.
* <p>
* The interactions with memory are the same
* as of a write to an ordinary variable, such as an array element or a
* non-volatile, non-final field.
* <p>
* In particular, unrelated threads may fail to see the updated target
* until they perform a read from memory.
* Stronger guarantees can be created by putting appropriate operations
* into the bootstrap method and/or the target methods used
* at any given call site.
*
* @param newTarget the new target
* @throws NullPointerException if the proposed new target is null
* @throws WrongMethodTypeException if the proposed new target
* has a method type that differs from the previous target
* @see #getTarget
*/
@Override public void setTarget(MethodHandle newTarget) {
checkTargetChange(this.target, newTarget);
setTargetNormal(newTarget);
}
/**
* {@inheritDoc}
*/
@Override
public final MethodHandle dynamicInvoker() {
return makeDynamicInvoker();
}
/**
* Performs a synchronization operation on each call site in the given array,
* forcing all other threads to throw away any cached values previously
* loaded from the target of any of the call sites.
* <p>
......@@ -115,19 +172,29 @@ public class MutableCallSite extends CallSite {
* <p>
* The overall effect is to force all future readers of each call site's target
* to accept the most recently stored value.
* ("Most recently" is reckoned relative to the {@code sync} itself.)
* Conversely, the {@code sync} call may block until all readers have
* ("Most recently" is reckoned relative to the {@code syncAll} itself.)
* Conversely, the {@code syncAll} call may block until all readers have
* (somehow) decached all previous versions of each call site's target.
* <p>
* To avoid race conditions, calls to {@code setTarget} and {@code sync}
* To avoid race conditions, calls to {@code setTarget} and {@code syncAll}
* should generally be performed under some sort of mutual exclusion.
* Note that reader threads may observe an updated target as early
* as the {@code setTarget} call that install the value
* (and before the {@code sync} that confirms the value).
* (and before the {@code syncAll} that confirms the value).
* On the other hand, reader threads may observe previous versions of
* the target until the {@code sync} call returns
* the target until the {@code syncAll} call returns
* (and after the {@code setTarget} that attempts to convey the updated version).
* <p>
* This operation is likely to be expensive and should be used sparingly.
* If possible, it should be buffered for batch processing on sets of call sites.
* <p>
* If {@code sites} contains a null element,
* a {@code NullPointerException} will be raised.
* In this case, some non-null elements in the array may be
* processed before the method returns abnormally.
* Which elements these are (if any) is implementation-dependent.
*
* <h3>Java Memory Model details</h3>
* In terms of the Java Memory Model, this operation performs a synchronization
* action which is comparable in effect to the writing of a volatile variable
* by the current thread, and an eventual volatile read by every other thread
......@@ -171,18 +238,17 @@ public class MutableCallSite extends CallSite {
* thereby ensuring communication of the new target value.
* <p>
* As long as the constraints of the Java Memory Model are obeyed,
* implementations may delay the completion of a {@code sync}
* implementations may delay the completion of a {@code syncAll}
* operation while other threads ({@code T} above) continue to
* use previous values of {@code S}'s target.
* However, implementations are (as always) encouraged to avoid
* livelock, and to eventually require all threads to take account
* of the updated target.
* <p>
* This operation is likely to be expensive and should be used sparingly.
* If possible, it should be buffered for batch processing on sets of call sites.
*
* <p style="font-size:smaller;">
* (This is a static method on a set of call sites, not a
* virtual method on a single call site, for performance reasons.
* <em>Discussion:</em>
* For performance reasons, {@code syncAll} is not a virtual method
* on a single call site, but rather applies to a set of call sites.
* Some implementations may incur a large fixed overhead cost
* for processing one or more synchronization operations,
* but a small incremental cost for each additional call site.
......@@ -191,15 +257,25 @@ public class MutableCallSite extends CallSite {
* in order to make them notice the updated target value.
* However, it may be observed that a single call to synchronize
* several sites has the same formal effect as many calls,
* each on just one of the sites.)
* <p>
* each on just one of the sites.
*
* <p style="font-size:smaller;">
* <em>Implementation Note:</em>
* Simple implementations of {@code MutableCallSite} may use
* a volatile variable for the target of a mutable call site.
* In such an implementation, the {@code sync} method can be a no-op,
* In such an implementation, the {@code syncAll} method can be a no-op,
* and yet it will conform to the JMM behavior documented above.
*
* @param sites an array of call sites to be synchronized
* @throws NullPointerException if the {@code sites} array reference is null
* or the array contains a null
*/
public static void sync(MutableCallSite[] sites) {
public static void syncAll(MutableCallSite[] sites) {
if (sites.length == 0) return;
STORE_BARRIER.lazySet(0);
for (int i = 0; i < sites.length; i++) {
sites[i].getClass(); // trigger NPE on first null
}
// FIXME: NYI
}
private static final AtomicInteger STORE_BARRIER = new AtomicInteger();
......
jdk/src/share/classes/java/dyn/Switcher.java → jdk/src/share/classes/java/dyn/SwitchPoint.java
浏览文件 @ d7393144
/*
* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
......@@ -27,68 +27,84 @@ package java.dyn;
/**
* <p>
* A {@code Switcher} is an object which can publish state transitions to other threads.
* A switcher is initially in the <em>valid</em> state, but may at any time be
* A {@code SwitchPoint} is an object which can publish state transitions to other threads.
* A switch point is initially in the <em>valid</em> state, but may at any time be
* changed to the <em>invalid</em> state. Invalidation cannot be reversed.
* A switch point can combine a <em>guarded pair</em> of method handles into a
* <em>guarded delegator</em>.
* The guarded delegator is a method handle which delegates to one of the old method handles.
* The state of the switch point determines which of the two gets the delegation.
* <p>
* A single switcher may be used to create any number of guarded method handle pairs.
* Each guarded pair is wrapped in a new method handle {@code M},
* which is permanently associated with the switcher that created it.
* A single switch point may be used to control any number of method handles.
* (Indirectly, therefore, it can control any number of call sites.)
* This is done by using the single switch point as a factory for combining
* any number of guarded method handle pairs into guarded delegators.
* <p>
* When a guarded delegator is created from a guarded pair, the pair
* is wrapped in a new method handle {@code M},
* which is permanently associated with the switch point that created it.
* Each pair consists of a target {@code T} and a fallback {@code F}.
* While the switcher is valid, invocations to {@code M} are delegated to {@code T}.
* While the switch point is valid, invocations to {@code M} are delegated to {@code T}.
* After it is invalidated, invocations are delegated to {@code F}.
* <p>
* Invalidation is global and immediate, as if the switcher contained a
* Invalidation is global and immediate, as if the switch point contained a
* volatile boolean variable consulted on every call to {@code M}.
* The invalidation is also permanent, which means the switcher
* The invalidation is also permanent, which means the switch point
* can change state only once.
* The switch point will always delegate to {@code F} after being invalidated.
* At that point {@code guardWithTest} may ignore {@code T} and return {@code F}.
* <p>
* Here is an example of a switcher in action:
* Here is an example of a switch point in action:
* <blockquote><pre>
MethodType MT_str2 = MethodType.methodType(String.class, String.class);
MethodHandle MH_strcat = MethodHandles.lookup()
.findVirtual(String.class, "concat", MT_str2);
Switcher switcher = new Switcher();
// the following steps may be repeated to re-use the same switcher:
SwitchPoint spt = new SwitchPoint();
// the following steps may be repeated to re-use the same switch point:
MethodHandle worker1 = strcat;
MethodHandle worker2 = MethodHandles.permuteArguments(strcat, MT_str2, 1, 0);
MethodHandle worker = switcher.guardWithTest(worker1, worker2);
MethodHandle worker = spt.guardWithTest(worker1, worker2);
assertEquals("method", (String) worker.invokeExact("met", "hod"));
switcher.invalidate();
SwitchPoint.invalidateAll(new SwitchPoint[]{ spt });
assertEquals("hodmet", (String) worker.invokeExact("met", "hod"));
* </pre></blockquote>
* <p>
* <p style="font-size:smaller;">
* <em>Discussion:</em>
* Switch points are useful without subclassing. They may also be subclassed.
* This may be useful in order to associate application-specific invalidation logic
* with the switch point.
* <p style="font-size:smaller;">
* <em>Implementation Note:</em>
* A switcher behaves as if implemented on top of {@link MutableCallSite},
* A switch point behaves as if implemented on top of {@link MutableCallSite},
* approximately as follows:
* <blockquote><pre>
public class Switcher {
public class SwitchPoint {
private static final MethodHandle
K_true = MethodHandles.constant(boolean.class, true),
K_false = MethodHandles.constant(boolean.class, false);
private final MutableCallSite mcs;
private final MethodHandle mcsInvoker;
public Switcher() {
public SwitchPoint() {
this.mcs = new MutableCallSite(K_true);
this.mcsInvoker = mcs.dynamicInvoker();
}
public MethodHandle guardWithTest(
MethodHandle target, MethodHandle fallback) {
// Note: mcsInvoker is of type boolean().
// Note: mcsInvoker is of type ()boolean.
// Target and fallback may take any arguments, but must have the same type.
return MethodHandles.guardWithTest(this.mcsInvoker, target, fallback);
}
public static void invalidateAll(Switcher[] switchers) {
List<MutableCallSite> mcss = new ArrayList<>();
for (Switcher s : switchers) mcss.add(s.mcs);
public static void invalidateAll(SwitchPoint[] spts) {
List&lt;MutableCallSite&gt; mcss = new ArrayList&lt;&gt;();
for (SwitchPoint spt : spts) mcss.add(spt.mcs);
for (MutableCallSite mcs : mcss) mcs.setTarget(K_false);
MutableCallSite.sync(mcss.toArray(new MutableCallSite[0]));
MutableCallSite.syncAll(mcss.toArray(new MutableCallSite[0]));
}
}
* </pre></blockquote>
* @author Remi Forax, JSR 292 EG
*/
public class Switcher {
public class SwitchPoint {
private static final MethodHandle
K_true = MethodHandles.constant(boolean.class, true),
K_false = MethodHandles.constant(boolean.class, false);
......@@ -96,19 +112,26 @@ public class Switcher {
private final MutableCallSite mcs;
private final MethodHandle mcsInvoker;
/** Create a switcher. */
public Switcher() {
/**
* Creates a new switch point.
*/
public SwitchPoint() {
this.mcs = new MutableCallSite(K_true);
this.mcsInvoker = mcs.dynamicInvoker();
}
/**
* Return a method handle which always delegates either to the target or the fallback.
* The method handle will delegate to the target exactly as long as the switcher is valid.
* Returns a method handle which always delegates either to the target or the fallback.
* The method handle will delegate to the target exactly as long as the switch point is valid.
* After that, it will permanently delegate to the fallback.
* <p>
* The target and fallback must be of exactly the same method type,
* and the resulting combined method handle will also be of this type.
*
* @param target the method handle selected by the switch point as long as it is valid
* @param fallback the method handle selected by the switch point after it is invalidated
* @return a combined method handle which always calls either the target or fallback
* @throws NullPointerException if either argument is null
* @see MethodHandles#guardWithTest
*/
public MethodHandle guardWithTest(MethodHandle target, MethodHandle fallback) {
......@@ -117,14 +140,56 @@ public class Switcher {
return MethodHandles.guardWithTest(mcsInvoker, target, fallback);
}
/** Set all of the given switchers into the invalid state. */
public static void invalidateAll(Switcher[] switchers) {
MutableCallSite[] sites = new MutableCallSite[switchers.length];
int fillp = 0;
for (Switcher switcher : switchers) {
sites[fillp++] = switcher.mcs;
switcher.mcs.setTarget(K_false);
/**
* Sets all of the given switch points into the invalid state.
* After this call executes, no thread will observe any of the
* switch points to be in a valid state.
* <p>
* This operation is likely to be expensive and should be used sparingly.
* If possible, it should be buffered for batch processing on sets of switch points.
* <p>
* If {@code switchPoints} contains a null element,
* a {@code NullPointerException} will be raised.
* In this case, some non-null elements in the array may be
* processed before the method returns abnormally.
* Which elements these are (if any) is implementation-dependent.
*
* <p style="font-size:smaller;">
* <em>Discussion:</em>
* For performance reasons, {@code invalidateAll} is not a virtual method
* on a single switch point, but rather applies to a set of switch points.
* Some implementations may incur a large fixed overhead cost
* for processing one or more invalidation operations,
* but a small incremental cost for each additional invalidation.
* In any case, this operation is likely to be costly, since
* other threads may have to be somehow interrupted
* in order to make them notice the updated switch point state.
* However, it may be observed that a single call to invalidate
* several switch points has the same formal effect as many calls,
* each on just one of the switch points.
*
* <p style="font-size:smaller;">
* <em>Implementation Note:</em>
* Simple implementations of {@code SwitchPoint} may use
* a private {@link MutableCallSite} to publish the state of a switch point.
* In such an implementation, the {@code invalidateAll} method can
* simply change the call site's target, and issue one call to
* {@linkplain MutableCallSite#syncAll synchronize} all the
* private call sites.
*
* @param switchPoints an array of call sites to be synchronized
* @throws NullPointerException if the {@code switchPoints} array reference is null
* or the array contains a null
*/
public static void invalidateAll(SwitchPoint[] switchPoints) {
if (switchPoints.length == 0) return;
MutableCallSite[] sites = new MutableCallSite[switchPoints.length];
for (int i = 0; i < switchPoints.length; i++) {
SwitchPoint spt = switchPoints[i];
if (spt == null) break; // MSC.syncAll will trigger a NPE
sites[i] = spt.mcs;
spt.mcs.setTarget(K_false);
}
MutableCallSite.sync(sites);
MutableCallSite.syncAll(sites);
}
}
jdk/src/share/classes/java/dyn/VolatileCallSite.java
浏览文件 @ d7393144
/*
* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
......@@ -34,7 +34,7 @@ import java.util.List;
* There may be a performance penalty for such tight coupling between threads.
* <p>
* Unlike {@code MutableCallSite}, there is no
* {@linkplain MutableCallSite#sync sync operation} on volatile
* {@linkplain MutableCallSite#syncAll syncAll operation} on volatile
* call sites, since every write to a volatile variable is implicitly
* synchronized with reader threads.
* <p>
......@@ -44,36 +44,68 @@ import java.util.List;
* @author John Rose, JSR 292 EG
*/
public class VolatileCallSite extends CallSite {
/** Create a call site with a volatile target.
* The initial target is set to a method handle
* of the given type which will throw {@code IllegalStateException}.
/**
* Creates a call site with a volatile binding to its target.
* The initial target is set to a method handle
* of the given type which will throw an {@code IllegalStateException} if called.
* @param type the method type that this call site will have
* @throws NullPointerException if the proposed type is null
*/
public VolatileCallSite(MethodType type) {
super(type);
}
/** Create a call site with a volatile target.
* The target is set to the given value.
/**
* Creates a call site with a volatile binding to its target.
* The target is set to the given value.
* @param target the method handle that will be the initial target of the call site
* @throws NullPointerException if the proposed target is null
*/
public VolatileCallSite(MethodHandle target) {
super(target);
}
/** Internal override to nominally final getTarget. */
@Override
MethodHandle getTarget0() {
/**
* Returns the target method of the call site, which behaves
* like a {@code volatile} field of the {@code VolatileCallSite}.
* <p>
* The interactions of {@code getTarget} with memory are the same
* as of a read from a {@code volatile} field.
* <p>
* In particular, the current thread is required to issue a fresh
* read of the target from memory, and must not fail to see
* a recent update to the target by another thread.
*
* @return the linkage state of this call site, a method handle which can change over time
* @see #setTarget
*/
@Override public final MethodHandle getTarget() {
return getTargetVolatile();
}
/**
* Set the target method of this call site, as a volatile variable.
* Has the same effect as {@link CallSite#setTarget CallSite.setTarget}, with the additional
* effects associated with volatiles, in the Java Memory Model.
* Updates the target method of this call site, as a volatile variable.
* The type of the new target must agree with the type of the old target.
* <p>
* The interactions with memory are the same as of a write to a volatile field.
* In particular, any threads is guaranteed to see the updated target
* the next time it calls {@code getTarget}.
* @param newTarget the new target
* @throws NullPointerException if the proposed new target is null
* @throws WrongMethodTypeException if the proposed new target
* has a method type that differs from the previous target
* @see #getTarget
*/
@Override public void setTarget(MethodHandle newTarget) {
checkTargetChange(getTargetVolatile(), newTarget);
setTargetVolatile(newTarget);
}
/**
* {@inheritDoc}
*/
@Override
public final MethodHandle dynamicInvoker() {
return makeDynamicInvoker();
}
}
jdk/src/share/classes/java/dyn/WrongMethodTypeException.java
浏览文件 @ d7393144
......@@ -29,7 +29,7 @@ package java.dyn;
* Thrown to indicate that code has attempted to call a method handle
* via the wrong method type. As with the bytecode representation of
* normal Java method calls, method handle calls are strongly typed
* to a specific signature associated with a call site.
* to a specific type descriptor associated with a call site.
* <p>
* This exception may also be thrown when two method handles are
* composed, and the system detects that their types cannot be
......
jdk/src/share/classes/java/dyn/package-info.java
浏览文件 @ d7393144
......@@ -24,21 +24,20 @@
*/
/**
* This package contains dynamic language support provided directly by
* The {@code java.lang.invoke} package contains dynamic language support provided directly by
* the Java core class libraries and virtual machine.
*
* <p style="font-size:smaller;">
* <em>Historic Note:</em> In some early versions of Java SE 7,
* the name of this package is {@code java.dyn}.
* <p>
* Certain types in this package have special relations to dynamic
* language support in the virtual machine:
* <ul>
* <li>In source code, a call to
* {@link java.dyn.MethodHandle#invokeExact MethodHandle.invokeExact} or
* {@link java.dyn.MethodHandle#invokeGeneric MethodHandle.invokeGeneric}
* will compile and link, regardless of the requested type signature.
* As usual, the Java compiler emits an {@code invokevirtual}
* instruction with the given signature against the named method.
* The JVM links any such call (regardless of signature) to a dynamically
* typed method handle invocation. In the case of {@code invokeGeneric},
* argument and return value conversions are applied.
* <li>The class {@link java.dyn.MethodHandle MethodHandle} contains
* <a href="MethodHandle.html#sigpoly">signature polymorphic methods</a>
* which can be linked regardless of their type descriptor.
* Normally, method linkage requires exact matching of type descriptors.
* </li>
*
* <li>The JVM bytecode format supports immediate constants of
......@@ -58,12 +57,11 @@
* The final two bytes are reserved for future use and required to be zero.
* The constant pool reference of an {@code invokedynamic} instruction is to a entry
* with tag {@code CONSTANT_InvokeDynamic} (decimal 18). See below for its format.
* (The tag value 17 is also temporarily allowed. See below.)
* The entry specifies the following information:
* <ul>
* <li>a bootstrap method (a {@link java.dyn.MethodHandle MethodHandle} constant)</li>
* <li>the dynamic invocation name (a UTF8 string)</li>
* <li>the argument and return types of the call (encoded as a signature in a UTF8 string)</li>
* <li>the argument and return types of the call (encoded as a type descriptor in a UTF8 string)</li>
* <li>optionally, a sequence of additional <em>static arguments</em> to the bootstrap method ({@code ldc}-type constants)</li>
* </ul>
* <p>
......@@ -78,9 +76,9 @@
* as <a href="#bsm">described below</a>.
*
* <p style="font-size:smaller;">
* (Historic Note: Some older JVMs may allow the index of a {@code CONSTANT_NameAndType}
* <em>Historic Note:</em> Some older JVMs may allow the index of a {@code CONSTANT_NameAndType}
* instead of a {@code CONSTANT_InvokeDynamic}. In earlier, obsolete versions of this API, the
* bootstrap method was specified dynamically, in a per-class basis, during class initialization.)
* bootstrap method was specified dynamically, in a per-class basis, during class initialization.
*
* <h3><a name="indycon"></a>constant pool entries for {@code invokedynamic} instructions</h3>
* If a constant pool entry has the tag {@code CONSTANT_InvokeDynamic} (decimal 18),
......@@ -90,33 +88,21 @@
* <em>bootstrap method table</em>, which is stored in the {@code BootstrapMethods}
* attribute as <a href="#bsmattr">described below</a>.
* The second pair of bytes must be an index to a {@code CONSTANT_NameAndType}.
* This table is not part of the constant pool. Instead, it is stored
* in a class attribute named {@code BootstrapMethods}, described below.
* <p>
* The first index specifies a bootstrap method used by the associated dynamic call sites.
* The second index specifies the method name, argument types, and return type of the dynamic call site.
* The structure of such an entry is therefore analogous to a {@code CONSTANT_Methodref},
* except that the bootstrap method specifier reference replaces
* the {@code CONSTANT_Class} reference of a {@code CONSTANT_Methodref} entry.
* <p>
* Some older JVMs may allow an older constant pool entry tag of decimal 17.
* The format and behavior of a constant pool entry with this tag is identical to
* an entry with a tag of decimal 18, except that the first index refers directly
* to a {@code CONSTANT_MethodHandle} to use as the bootstrap method.
* This format does not require the bootstrap method table.
*
* <p style="font-size:smaller;">
* <em>(Note: The Proposed Final Draft of this specification is likely to support
* only the tag 18, not the tag 17.)</em>
*
* <h3><a name="mtcon"></a>constant pool entries for {@linkplain java.dyn.MethodType method types}</h3>
* If a constant pool entry has the tag {@code CONSTANT_MethodType} (decimal 16),
* it must contain exactly two more bytes, which must be an index to a {@code CONSTANT_Utf8}
* entry which represents a method type signature.
* entry which represents a method type descriptor.
* <p>
* The JVM will ensure that on first
* execution of an {@code ldc} instruction for this entry, a {@link java.dyn.MethodType MethodType}
* will be created which represents the signature.
* will be created which represents the type descriptor.
* Any classes mentioned in the {@code MethodType} will be loaded if necessary,
* but not initialized.
* Access checking and error reporting is performed exactly as it is for
......@@ -144,24 +130,58 @@
* The method handle itself will have a type and behavior determined by the subtag as follows:
* <code>
* <table border=1 cellpadding=5 summary="CONSTANT_MethodHandle subtypes">
* <tr><th>N</th><th>subtag name</th><th>member</th><th>MH type</th><th>MH behavior</th></tr>
* <tr><td>1</td><td>REF_getField</td><td>C.f:T</td><td>(C)T</td><td>getfield C.f:T</td></tr>
* <tr><td>2</td><td>REF_getStatic</td><td>C.f:T</td><td>(&nbsp;)T</td><td>getstatic C.f:T</td></tr>
* <tr><td>3</td><td>REF_putField</td><td>C.f:T</td><td>(C,T)void</td><td>putfield C.f:T</td></tr>
* <tr><td>4</td><td>REF_putStatic</td><td>C.f:T</td><td>(T)void</td><td>putstatic C.f:T</td></tr>
* <tr><td>5</td><td>REF_invokeVirtual</td><td>C.m(A*)T</td><td>(C,A*)T</td><td>invokevirtual C.m(A*)T</td></tr>
* <tr><td>6</td><td>REF_invokeStatic</td><td>C.m(A*)T</td><td>(C,A*)T</td><td>invokestatic C.m(A*)T</td></tr>
* <tr><td>7</td><td>REF_invokeSpecial</td><td>C.m(A*)T</td><td>(C,A*)T</td><td>invokespecial C.m(A*)T</td></tr>
* <tr><td>8</td><td>REF_newInvokeSpecial</td><td>C.&lt;init&gt;(A*)void</td><td>(A*)C</td><td>new C; dup; invokespecial C.&lt;init&gt;(A*)void</td></tr>
* <tr><td>9</td><td>REF_invokeInterface</td><td>C.m(A*)T</td><td>(C,A*)T</td><td>invokeinterface C.m(A*)T</td></tr>
* <tr><th>N</th><th>subtag name</th><th>member</th><th>MH type</th><th>bytecode behavior</th><th>lookup expression</th></tr>
* <tr><td>1</td><td>REF_getField</td><td>C.f:T</td><td>(C)T</td><td>getfield C.f:T</td>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findGetter findGetter(C.class,"f",T.class)}</td></tr>
* <tr><td>2</td><td>REF_getStatic</td><td>C.f:T</td><td>(&nbsp;)T</td><td>getstatic C.f:T</td>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findStaticGetter findStaticGetter(C.class,"f",T.class)}</td></tr>
* <tr><td>3</td><td>REF_putField</td><td>C.f:T</td><td>(C,T)void</td><td>putfield C.f:T</td>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findSetter findSetter(C.class,"f",T.class)}</td></tr>
* <tr><td>4</td><td>REF_putStatic</td><td>C.f:T</td><td>(T)void</td><td>putstatic C.f:T</td>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findStaticSetter findStaticSetter(C.class,"f",T.class)}</td></tr>
* <tr><td>5</td><td>REF_invokeVirtual</td><td>C.m(A*)T</td><td>(C,A*)T</td><td>invokevirtual C.m(A*)T</td>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findVirtual findVirtual(C.class,"m",MT)}</td></tr>
* <tr><td>6</td><td>REF_invokeStatic</td><td>C.m(A*)T</td><td>(C,A*)T</td><td>invokestatic C.m(A*)T</td>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findStatic findStatic(C.class,"m",MT)}</td></tr>
* <tr><td>7</td><td>REF_invokeSpecial</td><td>C.m(A*)T</td><td>(C,A*)T</td><td>invokespecial C.m(A*)T</td>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findSpecial findSpecial(C.class,"m",MT,this.class)}</td></tr>
* <tr><td>8</td><td>REF_newInvokeSpecial</td><td>C.&lt;init&gt;(A*)void</td><td>(A*)C</td><td>new C; dup; invokespecial C.&lt;init&gt;(A*)void</td>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findConstructor findConstructor(C.class,MT)}</td></tr>
* <tr><td>9</td><td>REF_invokeInterface</td><td>C.m(A*)T</td><td>(C,A*)T</td><td>invokeinterface C.m(A*)T</td>
* <td>{@linkplain java.dyn.MethodHandles.Lookup#findVirtual findVirtual(C.class,"m",MT)}</td></tr>
* </table>
* </code>
* Here, the type {@code C} is taken from the {@code CONSTANT_Class} reference associated
* with the {@code CONSTANT_NameAndType} descriptor.
* The field name {@code f} or method name {@code m} is taken from the {@code CONSTANT_NameAndType}
* as is the result type {@code T} and (in the case of a method or constructor) the argument type sequence
* {@code A*}.
* <p>
* Each method handle constant has an equivalent instruction sequence called its <em>bytecode behavior</em>.
* In general, creating a method handle constant can be done in exactly the same circumstances that
* the JVM would successfully resolve the symbolic references in the bytecode behavior.
* Also, the type of a method handle constant is such that a valid {@code invokeExact} call
* on the method handle has exactly the same JVM stack effects as the <em>bytecode behavior</em>.
* Finally, calling a method handle constant on a valid set of arguments has exactly the same effect
* and returns the same result (if any) as the corresponding <em>bytecode behavior</em>.
* <p>
* Each method handle constant also has an equivalent reflective <em>lookup expression</em>,
* which is a query to a method in {@link java.dyn.MethodHandles.Lookup}.
* In the example lookup method expression given in the table above, the name {@code MT}
* stands for a {@code MethodType} built from {@code T} and the sequence of argument types {@code A*}.
* (Note that the type {@code C} is not prepended to the query type {@code MT} even if the member is non-static.)
* In the case of {@code findSpecial}, the name {@code this.class} refers to the class containing
* the bytecodes.
* <p>
* The special name {@code <clinit>} is not allowed.
* The special name {@code <init>} is not allowed except for subtag 8 as shown.
* <p>
* The JVM verifier and linker apply the same access checks and restrictions for these references as for the hypothetical
* bytecode instructions specified in the last column of the table. In particular, method handles to
* bytecode instructions specified in the last column of the table.
* A method handle constant will successfully resolve to a method handle if the symbolic references
* of the corresponding bytecode instruction(s) would also resolve successfully.
* Otherwise, an attempt to resolve the constant will throw equivalent linkage errors.
* In particular, method handles to
* private and protected members can be created in exactly those classes for which the corresponding
* normal accesses are legal.
* <p>
......@@ -186,14 +206,14 @@
* by the execution of {@code invokedynamic} and {@code ldc} instructions.
* (Roughly speaking, this means that every use of a constant pool entry
* must lead to the same outcome.
* If the resoultion succeeds, the same object reference is produced
* If the resolution succeeds, the same object reference is produced
* by every subsequent execution of the same instruction.
* If the resolution of the constant causes an error to occur,
* the same error will be re-thrown on every subsequent attempt
* to use this particular constant.)
* <p>
* Constants created by the resolution of these constant pool types are not necessarily
* interned. Except for {@link CONSTANT_Class} and {@link CONSTANT_String} entries,
* interned. Except for {@code CONSTANT_Class} and {@code CONSTANT_String} entries,
* two distinct constant pool entries might not resolve to the same reference
* even if they contain the same symbolic reference.
*
......@@ -207,31 +227,31 @@
* <p>
* Each {@code invokedynamic} instruction statically specifies its own
* bootstrap method as a constant pool reference.
* The constant pool reference also specifies the call site's name and type signature,
* The constant pool reference also specifies the call site's name and type descriptor,
* just like {@code invokevirtual} and the other invoke instructions.
* <p>
* Linking starts with resolving the constant pool entry for the
* bootstrap method, and resolving a {@link java.dyn.MethodType MethodType} object for
* the type signature of the dynamic call site.
* the type descriptor of the dynamic call site.
* This resolution process may trigger class loading.
* It may therefore throw an error if a class fails to load.
* This error becomes the abnormal termination of the dynamic
* call site execution.
* Linkage does not trigger class initialization.
* <p>
* Next, the bootstrap method call is started, with four or five values being stacked:
* Next, the bootstrap method call is started, with at least four values being stacked:
* <ul>
* <li>a {@code MethodHandle}, the resolved bootstrap method itself </li>
* <li>a {@code MethodHandles.Lookup}, a lookup object on the <em>caller class</em> in which dynamic call site occurs </li>
* <li>a {@code String}, the method name mentioned in the call site </li>
* <li>a {@code MethodType}, the resolved type signature of the call </li>
* <li>optionally, a single object representing one or more <a href="#args">additional static arguments</a> </li>
* <li>a {@code MethodType}, the resolved type descriptor of the call </li>
* <li>optionally, one or more <a href="#args">additional static arguments</a> </li>
* </ul>
* The method handle is then applied to the other values as if by
* {@link java.dyn.MethodHandle#invokeGeneric invokeGeneric}.
* The returned result must be a {@link java.dyn.CallSite CallSite} (or a subclass).
* The type of the call site's target must be exactly equal to the type
* derived from the dynamic call site signature and passed to
* derived from the dynamic call site's type descriptor and passed to
* the bootstrap method.
* The call site then becomes permanently linked to the dynamic call site.
* <p>
......@@ -299,11 +319,11 @@
* chosen target object.
*
* <p style="font-size:smaller;">
* (Historic Note: Unlike some previous versions of this specification,
* <em>Historic Note:</em> Unlike some previous versions of this specification,
* these rules do not enable the JVM to duplicate dynamic call sites,
* or to issue &ldquo;causeless&rdquo; bootstrap method calls.
* Every dynamic call site transitions at most once from unlinked to linked,
* just before its first invocation.)
* just before its first invocation.
*
* <h3><a name="bsmattr">the {@code BootstrapMethods} attribute </h3>
* Each {@code CONSTANT_InvokeDynamic} entry contains an index which references
......@@ -349,7 +369,6 @@
* Static arguments are specified constant pool indexes stored in the {@code BootstrapMethods} attribute.
* Before the bootstrap method is invoked, each index is used to compute an {@code Object}
* reference to the indexed value in the constant pool.
* If the value is a primitive type, it is converted to a reference by boxing conversion.
* The valid constant pool entries are listed in this table:
* <code>
* <table border=1 cellpadding=5 summary="Static argument types">
......@@ -374,6 +393,9 @@
* at most 252 extra arguments can be supplied.)
* The bootstrap method will be invoked as if by either {@code invokeGeneric}
* or {@code invokeWithArguments}. (There is no way to tell the difference.)
* <p>
* The normal argument conversion rules for {@code invokeGeneric} apply to all stacked arguments.
* For example, if a pushed value is a primitive type, it may be converted to a reference by boxing conversion.
* If the bootstrap method is a variable arity method (its modifier bit {@code 0x0080} is set),
* then some or all of the arguments specified here may be collected into a trailing array parameter.
* (This is not a special rule, but rather a useful consequence of the interaction
......@@ -430,11 +452,6 @@ struct CONSTANT_MethodType_info {
u1 tag = 16;
u2 descriptor_index; // index to CONSTANT_Utf8, as in NameAndType
}
struct CONSTANT_InvokeDynamic_17_info {
u1 tag = 17;
u2 bootstrap_method_index; // index to CONSTANT_MethodHandle
u2 name_and_type_index; // same as for CONSTANT_Methodref, etc.
}
struct CONSTANT_InvokeDynamic_info {
u1 tag = 18;
u2 bootstrap_method_attr_index; // index into BootstrapMethods_attr
......@@ -451,9 +468,6 @@ struct BootstrapMethods_attr {
} bootstrap_methods[bootstrap_method_count];
}
* </pre></blockquote>
* <p>
* <em>Note: The Proposed Final Draft of JSR 292 may remove the constant tag 17,
* for the sake of simplicity.</em>
*
* @author John Rose, JSR 292 EG
*/
......
jdk/src/share/classes/sun/dyn/AdapterMethodHandle.java
浏览文件 @ d7393144
......@@ -962,7 +962,7 @@ public class AdapterMethodHandle extends BoundMethodHandle {
@Override
public String toString() {
return nonAdapter((MethodHandle)vmtarget).toString();
return MethodHandleImpl.getNameString(IMPL_TOKEN, nonAdapter((MethodHandle)vmtarget), this);
}
private static MethodHandle nonAdapter(MethodHandle mh) {
......
jdk/src/share/classes/sun/dyn/FromGeneric.java
浏览文件 @ d7393144
/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2008, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
......@@ -28,6 +28,7 @@ package sun.dyn;
import java.dyn.*;
import java.lang.reflect.*;
import sun.dyn.util.*;
import static sun.dyn.MethodTypeImpl.invokers;
/**
* Adapters which mediate between incoming calls which are generic
......@@ -128,7 +129,7 @@ class FromGeneric {
MethodType targetType, MethodType internalType) {
// All the adapters we have here have reference-untyped internal calls.
assert(internalType == internalType.erase());
MethodHandle invoker = MethodHandles.exactInvoker(targetType);
MethodHandle invoker = invokers(targetType).exactInvoker();
// cast all narrow reference types, unbox all primitive arguments:
MethodType fixArgsType = internalType.changeReturnType(targetType.returnType());
MethodHandle fixArgs = AdapterMethodHandle.convertArguments(Access.TOKEN,
......
jdk/src/share/classes/sun/dyn/InvokeGeneric.java
浏览文件 @ d7393144
......@@ -28,6 +28,7 @@ package sun.dyn;
import java.dyn.*;
import java.lang.reflect.*;
import sun.dyn.util.*;
import static sun.dyn.MethodTypeImpl.invokers;
/**
* Adapters which manage MethodHanndle.invokeGeneric calls.
......@@ -87,7 +88,7 @@ class InvokeGeneric {
private MethodHandle makePostDispatchInvoker() {
// Take (MH'; MT, MH; A...) and run MH'(MT, MH; A...).
MethodType invokerType = erasedCallerType.insertParameterTypes(0, EXTRA_ARGS);
return MethodHandles.exactInvoker(invokerType);
return invokers(invokerType).exactInvoker();
}
private MethodHandle dropDispatchArguments(MethodHandle targetInvoker) {
assert(targetInvoker.type().parameterType(0) == MethodHandle.class);
......
jdk/src/share/classes/sun/dyn/Invokers.java
浏览文件 @ d7393144
......@@ -104,8 +104,7 @@ public class Invokers {
MethodHandle vaInvoker = spreadInvokers[objectArgCount];
if (vaInvoker != null) return vaInvoker;
MethodHandle gInvoker = genericInvoker();
MethodType vaType = MethodType.genericMethodType(objectArgCount, true);
vaInvoker = MethodHandles.spreadArguments(gInvoker, invokerType(vaType));
vaInvoker = gInvoker.asSpreader(Object[].class, targetType.parameterCount() - objectArgCount);
spreadInvokers[objectArgCount] = vaInvoker;
return vaInvoker;
}
......
jdk/src/share/classes/sun/dyn/MethodHandleImpl.java
浏览文件 @ d7393144
......@@ -136,6 +136,8 @@ public abstract class MethodHandleImpl {
}
static {
if (!MethodHandleNatives.JVM_SUPPORT) // force init of native API
throw new InternalError("No JVM support for JSR 292");
// Force initialization of Lookup, so it calls us back as initLookup:
MethodHandles.publicLookup();
if (IMPL_LOOKUP_INIT == null)
......@@ -1216,14 +1218,24 @@ public abstract class MethodHandleImpl {
}
static <T extends Throwable> Empty throwException(T t) throws T { throw t; }
public static String getNameString(Access token, MethodHandle target) {
public static String getNameString(Access token, MethodHandle target, Object type) {
Access.check(token);
if (!(type instanceof MethodType)) {
if (type == null)
type = target.type();
else if (type instanceof MethodHandle)
type = ((MethodHandle)type).type();
}
MemberName name = null;
if (target != null)
name = MethodHandleNatives.getMethodName(target);
if (name == null)
return "invoke" + target.type();
return name.getName() + target.type();
return "invoke" + type;
return name.getName() + type;
}
public static String getNameString(Access token, MethodHandle target) {
return getNameString(token, target, null);
}
static String addTypeString(Object obj, MethodHandle target) {
......
jdk/src/share/classes/sun/dyn/ToGeneric.java
浏览文件 @ d7393144
/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2008, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
......@@ -31,6 +31,7 @@ import java.lang.reflect.InvocationTargetException;
import sun.dyn.util.ValueConversions;
import sun.dyn.util.Wrapper;
import static sun.dyn.MemberName.newIllegalArgumentException;
import static sun.dyn.MethodTypeImpl.invokers;
/**
* Adapters which mediate between incoming calls which are not generic
......@@ -72,7 +73,7 @@ class ToGeneric {
assert(entryType.erase() == entryType); // for now
// incoming call will first "forget" all reference types except Object
this.entryType = entryType;
MethodHandle invoker0 = MethodHandles.exactInvoker(entryType.generic());
MethodHandle invoker0 = invokers(entryType.generic()).exactInvoker();
MethodType rawEntryTypeInit;
Adapter ad = findAdapter(rawEntryTypeInit = entryType);
if (ad != null) {
......
jdk/src/share/classes/sun/dyn/WrapperInstance.java 0 → 100644
浏览文件 @ d7393144
/*
* Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.dyn;
import java.dyn.MethodHandle;
/**
* Private API used inside of java.dyn.MethodHandles.
* Interface implemented by every object which is produced by
* {@link java.dyn.MethodHandles#asInstance MethodHandles.asInstance}.
* The methods of this interface allow a caller to recover the parameters
* to {@code asInstance}.
* This allows applications to repeatedly convert between method handles
* and SAM objects, without the risk of creating unbounded delegation chains.
*/
public interface WrapperInstance {
/** Produce or recover a target method handle which is behaviorally
* equivalent to the SAM method of this object.
*/
public MethodHandle getWrapperInstanceTarget();
/** Recover the SAM type for which this object was created.
*/
public Class<?> getWrapperInstanceType();
}
jdk/test/java/dyn/InvokeGenericTest.java
浏览文件 @ d7393144
......@@ -320,7 +320,7 @@ public class InvokeGenericTest {
MethodHandle callable(List<Class<?>> params) {
MethodHandle mh = CALLABLES.get(params);
if (mh == null) {
mh = collectArguments(collector_MH, methodType(Object.class, params));
mh = collector_MH.asType(methodType(Object.class, params));
CALLABLES.put(params, mh);
}
return mh;
......
jdk/test/java/dyn/JavaDocExamplesTest.java
浏览文件 @ d7393144
......@@ -151,8 +151,8 @@ MethodHandles.Lookup lookup = MethodHandles.lookup();
// mt is (char,char)String
mt = MethodType.methodType(String.class, char.class, char.class);
mh = lookup.findVirtual(String.class, "replace", mt);
// (Ljava/lang/String;CC)Ljava/lang/String;
s = (String) mh.invokeExact("daddy",'d','n');
// invokeExact(Ljava/lang/String;CC)Ljava/lang/String;
assert(s.equals("nanny"));
// weakly typed invocation (using MHs.invoke)
s = (String) mh.invokeWithArguments("sappy", 'p', 'v');
......@@ -162,23 +162,24 @@ mt = MethodType.methodType(java.util.List.class, Object[].class);
mh = lookup.findStatic(java.util.Arrays.class, "asList", mt);
assert(mh.isVarargsCollector());
x = mh.invokeGeneric("one", "two");
// invokeGeneric(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/Object;
assert(x.equals(java.util.Arrays.asList("one","two")));
// mt is (Object,Object,Object)Object
mt = MethodType.genericMethodType(3);
mh = MethodHandles.collectArguments(mh, mt);
// mt is (Object,Object,Object)Object
// (Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
mh = mh.asType(mt);
x = mh.invokeExact((Object)1, (Object)2, (Object)3);
// invokeExact(Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
assert(x.equals(java.util.Arrays.asList(1,2,3)));
// mt is { =&gt; int}
mt = MethodType.methodType(int.class);
mh = lookup.findVirtual(java.util.List.class, "size", mt);
// (Ljava/util/List;)I
i = (int) mh.invokeExact(java.util.Arrays.asList(1,2,3));
// invokeExact(Ljava/util/List;)I
assert(i == 3);
mt = MethodType.methodType(void.class, String.class);
mh = lookup.findVirtual(java.io.PrintStream.class, "println", mt);
mh.invokeExact(System.out, "Hello, world.");
// invokeExact(Ljava/io/PrintStream;Ljava/lang/String;)V
{}
}}
}
......@@ -206,9 +207,7 @@ assertEquals("[three, thee, tee]", Arrays.toString((Object[])ls.get(0)));
MethodHandle vamh = publicLookup()
.findStatic(Arrays.class, "asList", methodType(List.class, Object[].class))
.asVarargsCollector(Object[].class);
MethodHandle invokeExact = publicLookup()
.findVirtual(MethodHandle.class, "invokeExact", vamh.type());
MethodHandle mh = invokeExact.bindTo(vamh);
MethodHandle mh = MethodHandles.exactInvoker(vamh.type()).bindTo(vamh);
assert(vamh.type().equals(mh.type()));
assertEquals("[1, 2, 3]", vamh.invokeGeneric(1,2,3).toString());
boolean failed = false;
......
jdk/test/java/dyn/MethodHandlesTest.java
浏览文件 @ d7393144
......@@ -323,6 +323,44 @@ public class MethodHandlesTest {
return x.getClass().getSimpleName();
}
/** Return lambda(arg...[arity]) { new Object[]{ arg... } } */
static MethodHandle varargsList(int arity) {
return ValueConversions.varargsList(arity);
}
/** Return lambda(arg...[arity]) { Arrays.asList(arg...) } */
static MethodHandle varargsArray(int arity) {
return ValueConversions.varargsArray(arity);
}
/** Variation of varargsList, but with the given rtype. */
static MethodHandle varargsList(int arity, Class<?> rtype) {
MethodHandle list = varargsList(arity);
MethodType listType = list.type().changeReturnType(rtype);
if (List.class.isAssignableFrom(rtype) || rtype == void.class || rtype == Object.class) {
// OK
} else if (rtype.isAssignableFrom(String.class)) {
if (LIST_TO_STRING == null)
try {
LIST_TO_STRING = PRIVATE.findStatic(PRIVATE.lookupClass(), "listToString",
MethodType.methodType(String.class, List.class));
} catch (Exception ex) { throw new RuntimeException(ex); }
list = MethodHandles.filterReturnValue(list, LIST_TO_STRING);
} else if (rtype.isPrimitive()) {
if (LIST_TO_INT == null)
try {
LIST_TO_INT = PRIVATE.findStatic(PRIVATE.lookupClass(), "listToInt",
MethodType.methodType(int.class, List.class));
} catch (Exception ex) { throw new RuntimeException(ex); }
list = MethodHandles.filterReturnValue(list, LIST_TO_INT);
list = MethodHandles.explicitCastArguments(list, listType);
} else {
throw new RuntimeException("varargsList: "+rtype);
}
return list.asType(listType);
}
private static MethodHandle LIST_TO_STRING, LIST_TO_INT;
private static String listToString(List x) { return x.toString(); }
private static int listToInt(List x) { return x.toString().hashCode(); }
static MethodHandle changeArgTypes(MethodHandle target, Class<?> argType) {
return changeArgTypes(target, 0, 999, argType);
}
......@@ -1302,7 +1340,7 @@ public class MethodHandlesTest {
}
MethodType inType = MethodType.methodType(Object.class, types);
MethodType outType = MethodType.methodType(Object.class, permTypes);
MethodHandle target = MethodHandles.convertArguments(ValueConversions.varargsList(outargs), outType);
MethodHandle target = MethodHandles.convertArguments(varargsList(outargs), outType);
MethodHandle newTarget = MethodHandles.permuteArguments(target, inType, reorder);
Object result = newTarget.invokeWithArguments(args);
Object expected = Arrays.asList(permArgs);
......@@ -1329,7 +1367,7 @@ public class MethodHandlesTest {
}
public void testSpreadArguments(Class<?> argType, int pos, int nargs) throws Throwable {
countTest();
MethodHandle target = ValueConversions.varargsArray(nargs);
MethodHandle target = varargsArray(nargs);
MethodHandle target2 = changeArgTypes(target, argType);
if (verbosity >= 3)
System.out.println("spread into "+target2+" ["+pos+".."+nargs+"]");
......@@ -1359,7 +1397,7 @@ public class MethodHandlesTest {
spreadParams.clear(); spreadParams.add(Object[].class);
}
MethodType newType = MethodType.methodType(Object.class, newParams);
MethodHandle result = MethodHandles.spreadArguments(target2, newType);
MethodHandle result = target2.asSpreader(Object[].class, nargs-pos).asType(newType);
Object[] returnValue;
if (pos == 0) {
// In the following line, the first cast implies
......@@ -1393,7 +1431,7 @@ public class MethodHandlesTest {
public void testCollectArguments(Class<?> argType, int pos, int nargs) throws Throwable {
countTest();
// fake up a MH with the same type as the desired adapter:
MethodHandle fake = ValueConversions.varargsArray(nargs);
MethodHandle fake = varargsArray(nargs);
fake = changeArgTypes(fake, argType);
MethodType newType = fake.type();
Object[] args = randomArgs(newType.parameterArray());
......@@ -1401,12 +1439,12 @@ public class MethodHandlesTest {
Object[] collectedArgs = Arrays.copyOfRange(args, 0, pos+1);
collectedArgs[pos] = Arrays.copyOfRange(args, pos, args.length);
// here is the MH which will witness the collected argument tail:
MethodHandle target = ValueConversions.varargsArray(pos+1);
MethodHandle target = varargsArray(pos+1);
target = changeArgTypes(target, 0, pos, argType);
target = changeArgTypes(target, pos, pos+1, Object[].class);
if (verbosity >= 3)
System.out.println("collect from "+Arrays.asList(args)+" ["+pos+".."+nargs+"]");
MethodHandle result = MethodHandles.collectArguments(target, newType);
MethodHandle result = target.asCollector(Object[].class, nargs-pos).asType(newType);
Object[] returnValue = (Object[]) result.invokeWithArguments(args);
// assertTrue(returnValue.length == pos+1 && returnValue[pos] instanceof Object[]);
// returnValue[pos] = Arrays.asList((Object[]) returnValue[pos]);
......@@ -1430,7 +1468,7 @@ public class MethodHandlesTest {
void testInsertArguments(int nargs, int pos, int ins) throws Throwable {
countTest();
MethodHandle target = ValueConversions.varargsArray(nargs + ins);
MethodHandle target = varargsArray(nargs + ins);
Object[] args = randomArgs(target.type().parameterArray());
List<Object> resList = Arrays.asList(args);
List<Object> argsToPass = new ArrayList<Object>(resList);
......@@ -1449,6 +1487,55 @@ public class MethodHandlesTest {
assertEquals(resList, res2List);
}
@Test
public void testFilterReturnValue() throws Throwable {
if (CAN_SKIP_WORKING) return;
startTest("filterReturnValue");
Class<?> classOfVCList = varargsList(1).invokeWithArguments(0).getClass();
assertTrue(List.class.isAssignableFrom(classOfVCList));
for (int nargs = 0; nargs <= 3; nargs++) {
for (Class<?> rtype : new Class[] { Object.class,
List.class,
int.class,
//byte.class, //FIXME: add this
//long.class, //FIXME: add this
CharSequence.class,
String.class }) {
testFilterReturnValue(nargs, rtype);
}
}
}
void testFilterReturnValue(int nargs, Class<?> rtype) throws Throwable {
countTest();
MethodHandle target = varargsList(nargs, rtype);
MethodHandle filter;
if (List.class.isAssignableFrom(rtype) || rtype.isAssignableFrom(List.class))
filter = varargsList(1); // add another layer of list-ness
else
filter = MethodHandles.identity(rtype);
filter = filter.asType(MethodType.methodType(target.type().returnType(), rtype));
Object[] argsToPass = randomArgs(nargs, Object.class);
if (verbosity >= 3)
System.out.println("filter "+target+" to "+rtype.getSimpleName()+" with "+filter);
MethodHandle target2 = MethodHandles.filterReturnValue(target, filter);
if (verbosity >= 4)
System.out.println("filtered target: "+target2);
// Simulate expected effect of filter on return value:
Object unfiltered = target.invokeWithArguments(argsToPass);
Object expected = filter.invokeWithArguments(unfiltered);
if (verbosity >= 4)
System.out.println("unfiltered: "+unfiltered+" : "+unfiltered.getClass().getSimpleName());
if (verbosity >= 4)
System.out.println("expected: "+expected+" : "+expected.getClass().getSimpleName());
Object result = target2.invokeWithArguments(argsToPass);
if (verbosity >= 3)
System.out.println("result: "+result+" : "+result.getClass().getSimpleName());
if (!expected.equals(result))
System.out.println("*** fail at n/rt = "+nargs+"/"+rtype.getSimpleName()+": "+Arrays.asList(argsToPass)+" => "+result+" != "+expected);
assertEquals(expected, result);
}
@Test
public void testFilterArguments() throws Throwable {
if (CAN_SKIP_WORKING) return;
......@@ -1462,8 +1549,8 @@ public class MethodHandlesTest {
void testFilterArguments(int nargs, int pos) throws Throwable {
countTest();
MethodHandle target = ValueConversions.varargsList(nargs);
MethodHandle filter = ValueConversions.varargsList(1);
MethodHandle target = varargsList(nargs);
MethodHandle filter = varargsList(1);
filter = MethodHandles.convertArguments(filter, filter.type().generic());
Object[] argsToPass = randomArgs(nargs, Object.class);
if (verbosity >= 3)
......@@ -1477,7 +1564,7 @@ public class MethodHandlesTest {
if (verbosity >= 3)
System.out.println("result: "+result);
if (!expected.equals(result))
System.out.println("*** fail at n/p = "+nargs+"/"+pos+": "+argsToPass+" => "+result);
System.out.println("*** fail at n/p = "+nargs+"/"+pos+": "+Arrays.asList(argsToPass)+" => "+result+" != "+expected);
assertEquals(expected, result);
}
......@@ -1497,8 +1584,8 @@ public class MethodHandlesTest {
void testFoldArguments(int nargs, int pos, int fold) throws Throwable {
if (pos != 0) return; // can fold only at pos=0 for now
countTest();
MethodHandle target = ValueConversions.varargsList(1 + nargs);
MethodHandle combine = ValueConversions.varargsList(fold).asType(MethodType.genericMethodType(fold));
MethodHandle target = varargsList(1 + nargs);
MethodHandle combine = varargsList(fold).asType(MethodType.genericMethodType(fold));
List<Object> argsToPass = Arrays.asList(randomArgs(nargs, Object.class));
if (verbosity >= 3)
System.out.println("fold "+target+" with "+combine);
......@@ -1514,7 +1601,7 @@ public class MethodHandlesTest {
if (verbosity >= 3)
System.out.println("result: "+result);
if (!expected.equals(result))
System.out.println("*** fail at n/p/f = "+nargs+"/"+pos+"/"+fold+": "+argsToPass+" => "+result);
System.out.println("*** fail at n/p/f = "+nargs+"/"+pos+"/"+fold+": "+argsToPass+" => "+result+" != "+expected);
assertEquals(expected, result);
}
......@@ -1533,7 +1620,7 @@ public class MethodHandlesTest {
void testDropArguments(int nargs, int pos, int drop) throws Throwable {
countTest();
MethodHandle target = ValueConversions.varargsArray(nargs);
MethodHandle target = varargsArray(nargs);
Object[] args = randomArgs(target.type().parameterArray());
MethodHandle target2 = MethodHandles.dropArguments(target, pos,
Collections.nCopies(drop, Object.class).toArray(new Class[0]));
......@@ -1584,7 +1671,8 @@ public class MethodHandlesTest {
boolean testRetCode = type.returnType() != void.class;
MethodHandle target = PRIVATE.findStatic(MethodHandlesTest.class, "invokee",
MethodType.genericMethodType(0, true));
target = MethodHandles.collectArguments(target, type);
assertTrue(target.isVarargsCollector());
target = target.asType(type);
Object[] args = randomArgs(type.parameterArray());
List<Object> targetPlusArgs = new ArrayList<Object>(Arrays.asList(args));
targetPlusArgs.add(0, target);
......@@ -1808,7 +1896,7 @@ public class MethodHandlesTest {
MethodHandle thrower = throwOrReturn.asType(MethodType.genericMethodType(2));
while (thrower.type().parameterCount() < nargs)
thrower = MethodHandles.dropArguments(thrower, thrower.type().parameterCount(), Object.class);
MethodHandle catcher = ValueConversions.varargsList(1+nargs).asType(MethodType.genericMethodType(1+nargs));
MethodHandle catcher = varargsList(1+nargs).asType(MethodType.genericMethodType(1+nargs));
MethodHandle target = MethodHandles.catchException(thrower,
thrown.getClass(), catcher);
assertEquals(thrower.type(), target.type());
......@@ -2079,7 +2167,7 @@ public class MethodHandlesTest {
CharSequence.class,
Example.class }) {
try {
MethodHandles.asInstance(ValueConversions.varargsArray(0), nonSAM);
MethodHandles.asInstance(varargsArray(0), nonSAM);
System.out.println("Failed to throw");
assertTrue(false);
} catch (IllegalArgumentException ex) {
......@@ -2183,22 +2271,22 @@ class ValueConversions {
Object a8, Object a9)
{ return makeList(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); }
static MethodHandle[] makeLists() {
ArrayList<MethodHandle> arrays = new ArrayList<MethodHandle>();
ArrayList<MethodHandle> lists = new ArrayList<MethodHandle>();
MethodHandles.Lookup lookup = IMPL_LOOKUP;
for (;;) {
int nargs = arrays.size();
int nargs = lists.size();
MethodType type = MethodType.genericMethodType(nargs).changeReturnType(List.class);
String name = "list";
MethodHandle array = null;
MethodHandle list = null;
try {
array = lookup.findStatic(ValueConversions.class, name, type);
list = lookup.findStatic(ValueConversions.class, name, type);
} catch (NoAccessException ex) {
}
if (array == null) break;
arrays.add(array);
if (list == null) break;
lists.add(list);
}
assert(arrays.size() == 11); // current number of methods
return arrays.toArray(new MethodHandle[0]);
assert(lists.size() == 11); // current number of methods
return lists.toArray(new MethodHandle[0]);
}
static final MethodHandle[] LISTS = makeLists();
......
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