/* * Copyright 2002-2014 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.core.annotation; import java.lang.annotation.Annotation; import java.lang.reflect.AnnotatedElement; import java.lang.reflect.Method; import java.util.Arrays; import java.util.Collections; import java.util.HashSet; import java.util.LinkedHashSet; import java.util.List; import java.util.Map; import java.util.Set; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.core.BridgeMethodResolver; import org.springframework.util.Assert; import org.springframework.util.ConcurrentReferenceHashMap; import org.springframework.util.ObjectUtils; import org.springframework.util.ReflectionUtils; /** * General utility methods for working with annotations, handling bridge methods * (which the compiler generates for generic declarations) as well as super methods * (for optional "annotation inheritance"). Note that none of this is * provided by the JDK's introspection facilities themselves. * *
As a general rule for runtime-retained annotations (e.g. for transaction
* control, authorization, or service exposure), always use the lookup methods
* on this class (e.g., {@link #findAnnotation(Method, Class)},
* {@link #getAnnotation(Method, Class)}, and {@link #getAnnotations(Method)})
* instead of the plain annotation lookup methods in the JDK. You can still
* explicitly choose between a get lookup on the given class level only
* ({@link #getAnnotation(Method, Class)}) and a find lookup in the entire
* inheritance hierarchy of the given method ({@link #findAnnotation(Method, Class)}).
*
* @author Rob Harrop
* @author Juergen Hoeller
* @author Sam Brannen
* @author Mark Fisher
* @author Chris Beams
* @author Phillip Webb
* @since 2.0
* @see java.lang.reflect.Method#getAnnotations()
* @see java.lang.reflect.Method#getAnnotation(Class)
*/
public abstract class AnnotationUtils {
/** The attribute name for annotations with a single element */
public static final String VALUE = "value";
private static final Map Correctly handles bridge {@link Method Methods} generated by the compiler.
* @param method the Method to retrieve annotations from
* @return the annotations found
* @see org.springframework.core.BridgeMethodResolver#findBridgedMethod(Method)
*/
public static Annotation[] getAnnotations(Method method) {
try {
return BridgeMethodResolver.findBridgedMethod(method).getAnnotations();
}
catch (Exception ex) {
// Assuming nested Class values not resolvable within annotation attributes...
logIntrospectionFailure(method, ex);
return null;
}
}
/**
* Get a single {@link Annotation} of {@code annotationType} from the supplied {@link Method}.
* Correctly handles bridge {@link Method Methods} generated by the compiler.
* @param method the method to look for annotations on
* @param annotationType the annotation type to look for
* @return the annotations found
* @see org.springframework.core.BridgeMethodResolver#findBridgedMethod(Method)
*/
public static A getAnnotation(Method method, Class annotationType) {
Method resolvedMethod = BridgeMethodResolver.findBridgedMethod(method);
return getAnnotation((AnnotatedElement) resolvedMethod, annotationType);
}
/**
* Get the possibly repeating {@link Annotation}s of {@code annotationType} from the
* supplied {@link Method}. Deals with both a single direct annotation and repeating
* annotations nested within a containing annotation.
* Correctly handles bridge {@link Method Methods} generated by the compiler.
* @param method the method to look for annotations on
* @param containerAnnotationType the class of the container that holds the annotations
* @param annotationType the annotation type to look for
* @return the annotations found
* @since 4.0
* @see org.springframework.core.BridgeMethodResolver#findBridgedMethod(Method)
*/
public static Set getRepeatableAnnotation(Method method,
Class extends Annotation> containerAnnotationType, Class annotationType) {
Method resolvedMethod = BridgeMethodResolver.findBridgedMethod(method);
return getRepeatableAnnotation((AnnotatedElement) resolvedMethod, containerAnnotationType, annotationType);
}
/**
* Get the possibly repeating {@link Annotation}s of {@code annotationType} from the
* supplied {@link AnnotatedElement}. Deals with both a single direct annotation and
* repeating annotations nested within a containing annotation.
* Correctly handles bridge {@link Method Methods} generated by the compiler.
* @param annotatedElement the element to look for annotations on
* @param containerAnnotationType the class of the container that holds the annotations
* @param annotationType the annotation type to look for
* @return the annotations found
* @since 4.0
* @see org.springframework.core.BridgeMethodResolver#findBridgedMethod(Method)
*/
public static Set getRepeatableAnnotation(AnnotatedElement annotatedElement,
Class extends Annotation> containerAnnotationType, Class annotationType) {
try {
if (annotatedElement.getAnnotations().length > 0) {
return new AnnotationCollector(containerAnnotationType, annotationType).getResult(annotatedElement);
}
}
catch (Exception ex) {
// Assuming nested Class values not resolvable within annotation attributes...
logIntrospectionFailure(annotatedElement, ex);
}
return Collections.emptySet();
}
/**
* Find a single {@link Annotation} of {@code annotationType} from the supplied
* {@link Method}, traversing its super methods (i.e., from superclasses and
* interfaces) if no annotation can be found on the given method itself.
* Annotations on methods are not inherited by default, so we need to handle
* this explicitly.
* @param method the method to look for annotations on
* @param annotationType the annotation type to look for
* @return the annotation found, or {@code null} if none
*/
@SuppressWarnings("unchecked")
public static A findAnnotation(Method method, Class annotationType) {
AnnotationCacheKey cacheKey = new AnnotationCacheKey(method, annotationType);
A result = (A) findAnnotationCache.get(cacheKey);
if (result == null) {
result = getAnnotation(method, annotationType);
Class> clazz = method.getDeclaringClass();
if (result == null) {
result = searchOnInterfaces(method, annotationType, clazz.getInterfaces());
}
while (result == null) {
clazz = clazz.getSuperclass();
if (clazz == null || clazz.equals(Object.class)) {
break;
}
try {
Method equivalentMethod = clazz.getDeclaredMethod(method.getName(), method.getParameterTypes());
result = getAnnotation(equivalentMethod, annotationType);
}
catch (NoSuchMethodException ex) {
// No equivalent method found
}
if (result == null) {
result = searchOnInterfaces(method, annotationType, clazz.getInterfaces());
}
}
if (result != null) {
findAnnotationCache.put(cacheKey, result);
}
}
return result;
}
private static A searchOnInterfaces(Method method, Class annotationType, Class>... ifcs) {
A annotation = null;
for (Class> iface : ifcs) {
if (isInterfaceWithAnnotatedMethods(iface)) {
try {
Method equivalentMethod = iface.getMethod(method.getName(), method.getParameterTypes());
annotation = getAnnotation(equivalentMethod, annotationType);
}
catch (NoSuchMethodException ex) {
// Skip this interface - it doesn't have the method...
}
if (annotation != null) {
break;
}
}
}
return annotation;
}
private static boolean isInterfaceWithAnnotatedMethods(Class> iface) {
Boolean flag = annotatedInterfaceCache.get(iface);
if (flag != null) {
return flag;
}
boolean found = false;
for (Method ifcMethod : iface.getMethods()) {
try {
if (ifcMethod.getAnnotations().length > 0) {
found = true;
break;
}
}
catch (Exception ex) {
// Assuming nested Class values not resolvable within annotation attributes...
logIntrospectionFailure(ifcMethod, ex);
}
}
annotatedInterfaceCache.put(iface, found);
return found;
}
/**
* Find a single {@link Annotation} of {@code annotationType} on the
* supplied {@link Class}, traversing its interfaces, annotations, and
* superclasses if the annotation is not present on the given class
* itself.
* This method explicitly handles class-level annotations which are not
* declared as {@link java.lang.annotation.Inherited inherited} as well
* as meta-annotations and annotations on interfaces.
* The algorithm operates as follows:
* Note: in this context, the term recursively means that the search
* process continues by returning to step #1 with the current interface,
* annotation, or superclass as the class to look for annotations on.
* @param clazz the class to look for annotations on
* @param annotationType the type of annotation to look for
* @return the annotation if found, or {@code null} if not found
*/
@SuppressWarnings("unchecked")
public static A findAnnotation(Class> clazz, Class annotationType) {
AnnotationCacheKey cacheKey = new AnnotationCacheKey(clazz, annotationType);
A result = (A) findAnnotationCache.get(cacheKey);
if (result == null) {
result = findAnnotation(clazz, annotationType, new HashSet If the supplied {@code clazz} is an interface, only the interface itself will be checked;
* the inheritance hierarchy for interfaces will not be traversed.
* The standard {@link Class} API does not provide a mechanism for determining which class
* in an inheritance hierarchy actually declares an {@link Annotation}, so we need to handle
* this explicitly.
* @param annotationType the annotation type to look for, both locally and as a meta-annotation
* @param clazz the class on which to check for the annotation (may be {@code null})
* @return the first {@link Class} in the inheritance hierarchy of the specified {@code clazz}
* which declares an annotation for the specified {@code annotationType}, or {@code null}
* if not found
* @see Class#isAnnotationPresent(Class)
* @see Class#getDeclaredAnnotations()
* @see #findAnnotationDeclaringClassForTypes(List, Class)
* @see #isAnnotationDeclaredLocally(Class, Class)
*/
public static Class> findAnnotationDeclaringClass(Class extends Annotation> annotationType, Class> clazz) {
Assert.notNull(annotationType, "Annotation type must not be null");
if (clazz == null || clazz.equals(Object.class)) {
return null;
}
if (isAnnotationDeclaredLocally(annotationType, clazz)) {
return clazz;
}
return findAnnotationDeclaringClass(annotationType, clazz.getSuperclass());
}
/**
* Find the first {@link Class} in the inheritance hierarchy of the specified
* {@code clazz} (including the specified {@code clazz} itself) which declares
* at least one of the specified {@code annotationTypes}, or {@code null} if
* none of the specified annotation types could be found.
* If the supplied {@code clazz} is {@code null}, {@code null} will be
* returned.
* If the supplied {@code clazz} is an interface, only the interface itself
* will be checked; the inheritance hierarchy for interfaces will not be traversed.
* The standard {@link Class} API does not provide a mechanism for determining
* which class in an inheritance hierarchy actually declares one of several
* candidate {@linkplain Annotation annotations}, so we need to handle this
* explicitly.
* @param annotationTypes the list of Class objects corresponding to the
* annotation types
* @param clazz the Class object corresponding to the class on which to check
* for the annotations, or {@code null}
* @return the first {@link Class} in the inheritance hierarchy of the specified
* {@code clazz} which declares an annotation of at least one of the specified
* {@code annotationTypes}, or {@code null} if not found
* @since 3.2.2
* @see Class#isAnnotationPresent(Class)
* @see Class#getDeclaredAnnotations()
* @see #findAnnotationDeclaringClass(Class, Class)
* @see #isAnnotationDeclaredLocally(Class, Class)
*/
public static Class> findAnnotationDeclaringClassForTypes(List Note: This method does not determine if the annotation is
* {@linkplain java.lang.annotation.Inherited inherited}. For greater clarity
* regarding inherited annotations, consider using
* {@link #isAnnotationInherited(Class, Class)} instead.
* @param annotationType the Class object corresponding to the annotation type
* @param clazz the Class object corresponding to the class on which to check for the annotation
* @return {@code true} if an annotation for the specified {@code annotationType}
* is declared locally on the supplied {@code clazz}
* @see Class#getDeclaredAnnotations()
* @see #isAnnotationInherited(Class, Class)
*/
public static boolean isAnnotationDeclaredLocally(Class extends Annotation> annotationType, Class> clazz) {
Assert.notNull(annotationType, "Annotation type must not be null");
Assert.notNull(clazz, "Class must not be null");
boolean declaredLocally = false;
try {
for (Annotation ann : clazz.getDeclaredAnnotations()) {
if (ann.annotationType().equals(annotationType)) {
declaredLocally = true;
break;
}
}
}
catch (Exception ex) {
// Assuming nested Class values not resolvable within annotation attributes...
logIntrospectionFailure(clazz, ex);
}
return declaredLocally;
}
/**
* Determine whether an annotation for the specified {@code annotationType} is present
* on the supplied {@code clazz} and is {@linkplain java.lang.annotation.Inherited inherited}
* (i.e., not declared locally for the class).
* If the supplied {@code clazz} is an interface, only the interface itself will be checked.
* In accordance with standard meta-annotation semantics, the inheritance hierarchy for interfaces
* will not be traversed. See the {@linkplain java.lang.annotation.Inherited Javadoc} for the
* {@code @Inherited} meta-annotation for further details regarding annotation inheritance.
* @param annotationType the Class object corresponding to the annotation type
* @param clazz the Class object corresponding to the class on which to check for the annotation
* @return {@code true} if an annotation for the specified {@code annotationType} is present
* on the supplied {@code clazz} and is inherited
* @see Class#isAnnotationPresent(Class)
* @see #isAnnotationDeclaredLocally(Class, Class)
*/
public static boolean isAnnotationInherited(Class extends Annotation> annotationType, Class> clazz) {
Assert.notNull(annotationType, "Annotation type must not be null");
Assert.notNull(clazz, "Class must not be null");
return (clazz.isAnnotationPresent(annotationType) && !isAnnotationDeclaredLocally(annotationType, clazz));
}
/**
* Determine if the supplied {@link Annotation} is defined in the core JDK
* {@code java.lang.annotation} package.
* @param annotation the annotation to check (never {@code null})
* @return {@code true} if the annotation is in the {@code java.lang.annotation} package
*/
public static boolean isInJavaLangAnnotationPackage(Annotation annotation) {
Assert.notNull(annotation, "Annotation must not be null");
return annotation.annotationType().getName().startsWith("java.lang.annotation");
}
/**
* Retrieve the given annotation's attributes as a {@link Map}, preserving all
* attribute types as-is.
* Note: This method actually returns an {@link AnnotationAttributes} instance.
* However, the {@code Map} signature has been preserved for binary compatibility.
* @param annotation the annotation to retrieve the attributes for
* @return the Map of annotation attributes, with attribute names as keys and
* corresponding attribute values as values
*/
public static Map Note: This method actually returns an {@link AnnotationAttributes} instance.
* However, the {@code Map} signature has been preserved for binary compatibility.
* @param annotation the annotation to retrieve the attributes for
* @param classValuesAsString whether to turn Class references into Strings (for
* compatibility with {@link org.springframework.core.type.AnnotationMetadata}
* or to preserve them as Class references
* @return the Map of annotation attributes, with attribute names as keys and
* corresponding attribute values as values
*/
public static Map This method provides fully recursive annotation reading capabilities on par with
* the reflection-based {@link org.springframework.core.type.StandardAnnotationMetadata}.
* @param annotation the annotation to retrieve the attributes for
* @param classValuesAsString whether to turn Class references into Strings (for
* compatibility with {@link org.springframework.core.type.AnnotationMetadata}
* or to preserve them as Class references
* @param nestedAnnotationsAsMap whether to turn nested Annotation instances into
* {@link AnnotationAttributes} maps (for compatibility with
* {@link org.springframework.core.type.AnnotationMetadata} or to preserve them as
* Annotation instances
* @return the annotation attributes (a specialized Map) with attribute names as keys
* and corresponding attribute values as values
* @since 3.1.1
*/
public static AnnotationAttributes getAnnotationAttributes(Annotation annotation, boolean classValuesAsString,
boolean nestedAnnotationsAsMap) {
AnnotationAttributes attrs = new AnnotationAttributes();
Method[] methods = annotation.annotationType().getDeclaredMethods();
for (Method method : methods) {
if (method.getParameterTypes().length == 0 && method.getReturnType() != void.class) {
try {
Object value = method.invoke(annotation);
attrs.put(method.getName(), adaptValue(value, classValuesAsString, nestedAnnotationsAsMap));
}
catch (Exception ex) {
throw new IllegalStateException("Could not obtain annotation attribute values", ex);
}
}
}
return attrs;
}
/**
* Adapt the given value according to the given class and nested annotation settings.
* @param value the annotation attribute value
* @param classValuesAsString whether to turn Class references into Strings (for
* compatibility with {@link org.springframework.core.type.AnnotationMetadata}
* or to preserve them as Class references
* @param nestedAnnotationsAsMap whether to turn nested Annotation instances into
* {@link AnnotationAttributes} maps (for compatibility with
* {@link org.springframework.core.type.AnnotationMetadata} or to preserve them as
* Annotation instances
* @return the adapted value, or the original value if no adaptation is needed
*/
static Object adaptValue(Object value, boolean classValuesAsString, boolean nestedAnnotationsAsMap) {
if (classValuesAsString) {
if (value instanceof Class) {
value = ((Class>) value).getName();
}
else if (value instanceof Class[]) {
Class>[] clazzArray = (Class[]) value;
String[] newValue = new String[clazzArray.length];
for (int i = 0; i < clazzArray.length; i++) {
newValue[i] = clazzArray[i].getName();
}
value = newValue;
}
}
if (nestedAnnotationsAsMap && value instanceof Annotation) {
return getAnnotationAttributes((Annotation) value, classValuesAsString, true);
}
else if (nestedAnnotationsAsMap && value instanceof Annotation[]) {
Annotation[] realAnnotations = (Annotation[]) value;
AnnotationAttributes[] mappedAnnotations = new AnnotationAttributes[realAnnotations.length];
for (int i = 0; i < realAnnotations.length; i++) {
mappedAnnotations[i] = getAnnotationAttributes(realAnnotations[i], classValuesAsString, true);
}
return mappedAnnotations;
}
else {
return value;
}
}
/**
* Retrieve the value of the {@code "value"} attribute of a
* single-element Annotation, given an annotation instance.
* @param annotation the annotation instance from which to retrieve the value
* @return the attribute value, or {@code null} if not found
* @see #getValue(Annotation, String)
*/
public static Object getValue(Annotation annotation) {
return getValue(annotation, VALUE);
}
/**
* Retrieve the value of a named attribute, given an annotation instance.
* @param annotation the annotation instance from which to retrieve the value
* @param attributeName the name of the attribute value to retrieve
* @return the attribute value, or {@code null} if not found
* @see #getValue(Annotation)
*/
public static Object getValue(Annotation annotation, String attributeName) {
try {
Method method = annotation.annotationType().getDeclaredMethod(attributeName);
ReflectionUtils.makeAccessible(method);
return method.invoke(annotation);
}
catch (Exception ex) {
return null;
}
}
/**
* Retrieve the default value of the {@code "value"} attribute
* of a single-element Annotation, given an annotation instance.
* @param annotation the annotation instance from which to retrieve the default value
* @return the default value, or {@code null} if not found
* @see #getDefaultValue(Annotation, String)
*/
public static Object getDefaultValue(Annotation annotation) {
return getDefaultValue(annotation, VALUE);
}
/**
* Retrieve the default value of a named attribute, given an annotation instance.
* @param annotation the annotation instance from which to retrieve the default value
* @param attributeName the name of the attribute value to retrieve
* @return the default value of the named attribute, or {@code null} if not found
* @see #getDefaultValue(Class, String)
*/
public static Object getDefaultValue(Annotation annotation, String attributeName) {
return getDefaultValue(annotation.annotationType(), attributeName);
}
/**
* Retrieve the default value of the {@code "value"} attribute
* of a single-element Annotation, given the {@link Class annotation type}.
* @param annotationType the annotation type for which the default value should be retrieved
* @return the default value, or {@code null} if not found
* @see #getDefaultValue(Class, String)
*/
public static Object getDefaultValue(Class extends Annotation> annotationType) {
return getDefaultValue(annotationType, VALUE);
}
/**
* Retrieve the default value of a named attribute, given the
* {@link Class annotation type}.
* @param annotationType the annotation type for which the default value should be retrieved
* @param attributeName the name of the attribute value to retrieve.
* @return the default value of the named attribute, or {@code null} if not found
* @see #getDefaultValue(Annotation, String)
*/
public static Object getDefaultValue(Class extends Annotation> annotationType, String attributeName) {
try {
return annotationType.getDeclaredMethod(attributeName).getDefaultValue();
}
catch (Exception ex) {
return null;
}
}
private static void logIntrospectionFailure(AnnotatedElement annotatedElement, Exception ex) {
Log loggerToUse = logger;
if (loggerToUse == null) {
loggerToUse = LogFactory.getLog(AnnotationUtils.class);
logger = loggerToUse;
}
if (loggerToUse.isInfoEnabled()) {
loggerToUse.info("Failed to introspect annotations on [" + annotatedElement + "]: " + ex);
}
}
/**
* Cache key for the AnnotatedElement cache.
*/
private static class AnnotationCacheKey {
private final AnnotatedElement element;
private final Class extends Annotation> annotationType;
public AnnotationCacheKey(AnnotatedElement element, Class extends Annotation> annotationType) {
this.element = element;
this.annotationType = annotationType;
}
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (!(other instanceof AnnotationCacheKey)) {
return false;
}
AnnotationCacheKey otherKey = (AnnotationCacheKey) other;
return (this.element.equals(otherKey.element) &&
ObjectUtils.nullSafeEquals(this.annotationType, otherKey.annotationType));
}
@Override
public int hashCode() {
return (this.element.hashCode() * 29 + this.annotationType.hashCode());
}
}
private static class AnnotationCollector {
private final Class extends Annotation> containerAnnotationType;
private final Class annotationType;
private final Set
*
*