Note that most of the features of this class are not 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)}). * *
An annotation is meta-present on an element if the annotation * is declared as a meta-annotation on some other annotation which is * present on the element. * *
Most {@code find*()} methods and some {@code get*()} methods in this * class provide support for finding annotations used as meta-annotations. * Consult the Javadoc for each method in this class for details. For support * for meta-annotations with attribute overrides in * composed annotations, use {@link AnnotatedElementUtils} instead. * *
The search algorithms used by methods in this class stop searching for
* an annotation once the first annotation of the specified type has been
* found. As a consequence, additional annotations of the specified type will
* be silently ignored.
*
* @author Rob Harrop
* @author Juergen Hoeller
* @author Sam Brannen
* @author Mark Fisher
* @author Chris Beams
* @author Phillip Webb
* @since 2.0
* @see AliasFor
* @see AnnotationAttributes
* @see AnnotatedElementUtils
* @see BridgeMethodResolver
* @see java.lang.reflect.AnnotatedElement#getAnnotations()
* @see java.lang.reflect.AnnotatedElement#getAnnotation(Class)
* @see java.lang.reflect.AnnotatedElement#getDeclaredAnnotations()
*/
public abstract class AnnotationUtils {
/**
* The attribute name for annotations with a single element.
*/
public static final String VALUE = "value";
/**
* An object that can be stored in {@link AnnotationAttributes} as a
* placeholder for an attribute's declared default value.
*/
private static final Object DEFAULT_VALUE_PLACEHOLDER = new String(" Note that this method supports only a single level of meta-annotations.
* For support for arbitrary levels of meta-annotations, use one of the
* {@code find*()} methods instead.
* @param ann the Annotation to check
* @param annotationType the annotation type to look for, both locally and as a meta-annotation
* @return the first matching annotation, or {@code null} if not found
* @since 4.0
*/
@SuppressWarnings("unchecked")
public static A getAnnotation(Annotation ann, Class annotationType) {
if (annotationType.isInstance(ann)) {
return synthesizeAnnotation((A) ann);
}
Class annotatedElement = ann.annotationType();
try {
return synthesizeAnnotation(annotatedElement.getAnnotation(annotationType), annotatedElement);
}
catch (Exception ex) {
// Assuming nested Class values not resolvable within annotation attributes...
handleIntrospectionFailure(annotatedElement, ex);
return null;
}
}
/**
* Get a single {@link Annotation} of {@code annotationType} from the supplied
* {@link AnnotatedElement}, where the annotation is either present or
* meta-present on the {@code AnnotatedElement}.
* Note that this method supports only a single level of meta-annotations.
* For support for arbitrary levels of meta-annotations, use
* {@link #findAnnotation(AnnotatedElement, Class)} instead.
* @param annotatedElement the {@code AnnotatedElement} from which to get the annotation
* @param annotationType the annotation type to look for, both locally and as a meta-annotation
* @return the first matching annotation, or {@code null} if not found
* @since 3.1
*/
public static A getAnnotation(AnnotatedElement annotatedElement, Class annotationType) {
try {
A annotation = annotatedElement.getAnnotation(annotationType);
if (annotation == null) {
for (Annotation metaAnn : annotatedElement.getAnnotations()) {
annotation = metaAnn.annotationType().getAnnotation(annotationType);
if (annotation != null) {
break;
}
}
}
return synthesizeAnnotation(annotation, annotatedElement);
}
catch (Exception ex) {
// Assuming nested Class values not resolvable within annotation attributes...
handleIntrospectionFailure(annotatedElement, ex);
return null;
}
}
/**
* Get a single {@link Annotation} of {@code annotationType} from the
* supplied {@link Method}, where the annotation is either present
* or meta-present on the method.
* Correctly handles bridge {@link Method Methods} generated by the compiler.
* Note that this method supports only a single level of meta-annotations.
* For support for arbitrary levels of meta-annotations, use
* {@link #findAnnotation(Method, Class)} instead.
* @param method the method to look for annotations on
* @param annotationType the annotation type to look for
* @return the first matching annotation, or {@code null} if not found
* @see org.springframework.core.BridgeMethodResolver#findBridgedMethod(Method)
* @see #getAnnotation(AnnotatedElement, Class)
*/
public static A getAnnotation(Method method, Class annotationType) {
Method resolvedMethod = BridgeMethodResolver.findBridgedMethod(method);
return getAnnotation((AnnotatedElement) resolvedMethod, annotationType);
}
/**
* Get all {@link Annotation Annotations} that are present on the
* supplied {@link AnnotatedElement}.
* Meta-annotations will not be searched.
* @param annotatedElement the Method, Constructor or Field to retrieve annotations from
* @return the annotations found, an empty array, or {@code null} if not
* resolvable (e.g. because nested Class values in annotation attributes
* failed to resolve at runtime)
* @since 4.0.8
*/
public static Annotation[] getAnnotations(AnnotatedElement annotatedElement) {
try {
return annotatedElement.getAnnotations();
}
catch (Exception ex) {
// Assuming nested Class values not resolvable within annotation attributes...
handleIntrospectionFailure(annotatedElement, ex);
}
return null;
}
/**
* Get all {@link Annotation Annotations} that are presentCorrectly handles bridge {@link Method Methods} generated by the compiler.
* Meta-annotations will not be searched.
* @param method the Method to retrieve annotations from
* @return the annotations found, an empty array, or {@code null} if not
* resolvable (e.g. because nested Class values in annotation attributes
* failed to resolve at runtime)
* @see org.springframework.core.BridgeMethodResolver#findBridgedMethod(Method)
* @see AnnotatedElement#getAnnotations()
*/
public static Annotation[] getAnnotations(Method method) {
try {
return BridgeMethodResolver.findBridgedMethod(method).getAnnotations();
}
catch (Exception ex) {
// Assuming nested Class values not resolvable within annotation attributes...
handleIntrospectionFailure(method, ex);
}
return null;
}
/**
* Get the repeatable {@link Annotation}s of {@code annotationType}
* from the supplied {@link Method}, where such annotations are either
* present or meta-present on the method.
* Handles both single annotations and annotations nested within a
* containing annotation.
* Correctly handles bridge {@link Method Methods} generated by the compiler.
* Meta-annotations will be searched if the annotation is not
* present on the supplied method.
* @param method the method to look for annotations on; never {@code null}
* @param containerAnnotationType the type of the container that holds the
* annotations; may be {@code null} if a container is not supported
* @param annotationType the annotation type to look for
* @return the annotations found or an empty set; never {@code null}
* @since 4.0
* @see org.springframework.core.BridgeMethodResolver#findBridgedMethod(Method)
* @see java.lang.annotation.Repeatable
*/
public static Set getRepeatableAnnotation(Method method,
Class containerAnnotationType, Class annotationType) {
Method resolvedMethod = BridgeMethodResolver.findBridgedMethod(method);
return getRepeatableAnnotation((AnnotatedElement) resolvedMethod, containerAnnotationType, annotationType);
}
/**
* Get the repeatable {@link Annotation}s of {@code annotationType}
* from the supplied {@link AnnotatedElement}, where such annotations are
* either present or meta-present on the element.
* Handles both single annotations and annotations nested within a
* containing annotation.
* Meta-annotations will be searched if the annotation is not
* present on the supplied element.
* @param annotatedElement the element to look for annotations on; never {@code null}
* @param containerAnnotationType the type of the container that holds the
* annotations; may be {@code null} if a container is not supported
* @param annotationType the annotation type to look for
* @return the annotations found or an empty set; never {@code null}
* @since 4.0
* @see java.lang.annotation.Repeatable
*/
public static Set getRepeatableAnnotation(AnnotatedElement annotatedElement,
Class 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...
handleIntrospectionFailure(annotatedElement, ex);
}
return Collections.emptySet();
}
/**
* Find a single {@link Annotation} of {@code annotationType} on the
* supplied {@link AnnotatedElement}.
* Meta-annotations will be searched if the annotation is not
* directly present on the supplied element.
* Warning: this method operates generically on
* annotated elements. In other words, this method does not execute
* specialized search algorithms for classes or methods. If you require
* the more specific semantics of {@link #findAnnotation(Class, Class)}
* or {@link #findAnnotation(Method, Class)}, invoke one of those methods
* instead.
* @param annotatedElement the {@code AnnotatedElement} on which to find the annotation
* @param annotationType the annotation type to look for, both locally and as a meta-annotation
* @return the first matching annotation, or {@code null} if not found
* @since 4.2
*/
public static A findAnnotation(AnnotatedElement annotatedElement, Class annotationType) {
// Do NOT store result in the findAnnotationCache since doing so could break
// findAnnotation(Class, Class) and findAnnotation(Method, Class).
return synthesizeAnnotation(findAnnotation(annotatedElement, annotationType, new HashSet Correctly handles bridge {@link Method Methods} generated by the compiler.
* Meta-annotations will be searched if the annotation is not
* directly present on the method.
* 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 first matching annotation, or {@code null} if not found
* @see #getAnnotation(Method, Class)
*/
@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) {
Method resolvedMethod = BridgeMethodResolver.findBridgedMethod(method);
result = findAnnotation((AnnotatedElement) resolvedMethod, annotationType);
if (result == null) {
result = searchOnInterfaces(method, annotationType, method.getDeclaringClass().getInterfaces());
}
Class clazz = method.getDeclaringClass();
while (result == null) {
clazz = clazz.getSuperclass();
if (clazz == null || Object.class == clazz) {
break;
}
try {
Method equivalentMethod = clazz.getDeclaredMethod(method.getName(), method.getParameterTypes());
Method resolvedEquivalentMethod = BridgeMethodResolver.findBridgedMethod(equivalentMethod);
result = findAnnotation((AnnotatedElement) resolvedEquivalentMethod, 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 synthesizeAnnotation(result, method);
}
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;
}
static boolean isInterfaceWithAnnotatedMethods(Class iface) {
Boolean found = annotatedInterfaceCache.get(iface);
if (found != null) {
return found.booleanValue();
}
found = Boolean.FALSE;
for (Method ifcMethod : iface.getMethods()) {
try {
if (ifcMethod.getAnnotations().length > 0) {
found = Boolean.TRUE;
break;
}
}
catch (Exception ex) {
// Assuming nested Class values not resolvable within annotation attributes...
handleIntrospectionFailure(ifcMethod, ex);
}
}
annotatedInterfaceCache.put(iface, found);
return found.booleanValue();
}
/**
* Find a single {@link Annotation} of {@code annotationType} on the
* supplied {@link Class}, traversing its interfaces, annotations, and
* superclasses if the annotation is not directly 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 first matching annotation, 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.
* Meta-annotations will not be searched.
* 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
* @param clazz the class to check for the annotation on (may be {@code null})
* @return the first {@link Class} in the inheritance hierarchy that
* declares an annotation of 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 annotationType, Class clazz) {
Assert.notNull(annotationType, "Annotation type must not be null");
if (clazz == null || Object.class == clazz) {
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)
* on which at least one of the specified {@code annotationTypes} is
* directly present.
* If the supplied {@code clazz} is an interface, only the interface
* itself will be checked; the inheritance hierarchy for interfaces will
* not be traversed.
* Meta-annotations will not be searched.
* 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 annotation types to look for
* @param clazz the class to check for the annotations on, or {@code null}
* @return the first {@link Class} in the inheritance hierarchy that
* 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 The supplied {@link Class} may represent any type.
* Meta-annotations will not be searched.
* 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 annotation type to look for
* @param clazz the class to check for the annotation on
* @return {@code true} if an annotation of the specified {@code annotationType}
* is directly present
* @see java.lang.Class#getDeclaredAnnotations()
* @see java.lang.Class#getDeclaredAnnotation(Class)
* @see #isAnnotationInherited(Class, Class)
*/
public static boolean isAnnotationDeclaredLocally(Class annotationType, Class clazz) {
Assert.notNull(annotationType, "Annotation type must not be null");
Assert.notNull(clazz, "Class must not be null");
try {
for (Annotation ann : clazz.getDeclaredAnnotations()) {
if (ann.annotationType().equals(annotationType)) {
return true;
}
}
}
catch (Exception ex) {
// Assuming nested Class values not resolvable within annotation attributes...
handleIntrospectionFailure(clazz, ex);
}
return false;
}
/**
* Determine whether an annotation of the specified {@code annotationType}
* is present on the supplied {@code clazz} and is
* {@linkplain java.lang.annotation.Inherited inherited} (i.e., not
* directly present).
* Meta-annotations will not be searched.
* If the supplied {@code clazz} is an interface, only the interface
* itself will be checked. In accordance with standard meta-annotation
* semantics in Java, 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 annotation type to look for
* @param clazz the class to check for the annotation on
* @return {@code true} if an annotation of the specified {@code annotationType}
* is present and inherited
* @see Class#isAnnotationPresent(Class)
* @see #isAnnotationDeclaredLocally(Class, Class)
*/
public static boolean isAnnotationInherited(Class 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 isInJavaLangAnnotationPackage(annotation.annotationType().getName());
}
/**
* Determine if the {@link Annotation} with the supplied name is defined
* in the core JDK {@code java.lang.annotation} package.
* @param annotationType the name of the annotation type to check (never {@code null} or empty)
* @return {@code true} if the annotation is in the {@code java.lang.annotation} package
* @since 4.2
*/
public static boolean isInJavaLangAnnotationPackage(String annotationType) {
Assert.hasText(annotationType, "annotationType must not be null or empty");
return annotationType.startsWith("java.lang.annotation");
}
/**
* Retrieve the given annotation's attributes as a {@link Map}, preserving all
* attribute types.
* Equivalent to calling {@link #getAnnotationAttributes(Annotation, boolean, boolean)}
* with the {@code classValuesAsString} and {@code nestedAnnotationsAsMap} parameters
* set to {@code false}.
* 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; never {@code null}
* @see #getAnnotationAttributes(AnnotatedElement, Annotation)
* @see #getAnnotationAttributes(Annotation, boolean, boolean)
* @see #getAnnotationAttributes(AnnotatedElement, Annotation, boolean, boolean)
*/
public static Map Equivalent to calling {@link #getAnnotationAttributes(Annotation, boolean, boolean)}
* with the {@code nestedAnnotationsAsMap} parameter set to {@code false}.
* 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 convert 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; never {@code null}
* @see #getAnnotationAttributes(Annotation, boolean, boolean)
*/
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 convert Class references into Strings (for
* compatibility with {@link org.springframework.core.type.AnnotationMetadata})
* or to preserve them as Class references
* @param nestedAnnotationsAsMap whether to convert nested annotations into
* {@link AnnotationAttributes} maps (for compatibility with
* {@link org.springframework.core.type.AnnotationMetadata}) or to preserve them as
* {@code Annotation} instances
* @return the annotation attributes (a specialized Map) with attribute names as keys
* and corresponding attribute values as values; never {@code null}
* @since 3.1.1
*/
public static AnnotationAttributes getAnnotationAttributes(Annotation annotation, boolean classValuesAsString,
boolean nestedAnnotationsAsMap) {
return getAnnotationAttributes(null, annotation, classValuesAsString, nestedAnnotationsAsMap);
}
/**
* Retrieve the given annotation's attributes as an {@link AnnotationAttributes} map.
* Equivalent to calling {@link #getAnnotationAttributes(AnnotatedElement, Annotation, boolean, boolean)}
* with the {@code classValuesAsString} and {@code nestedAnnotationsAsMap} parameters
* set to {@code false}.
* @param annotatedElement the element that is annotated with the supplied annotation;
* may be {@code null} if unknown
* @param annotation the annotation to retrieve the attributes for
* @return the annotation attributes (a specialized Map) with attribute names as keys
* and corresponding attribute values as values; never {@code null}
* @since 4.2
* @see #getAnnotationAttributes(AnnotatedElement, Annotation, boolean, boolean)
*/
public static AnnotationAttributes getAnnotationAttributes(AnnotatedElement annotatedElement, Annotation annotation) {
return getAnnotationAttributes(annotatedElement, annotation, false, false);
}
/**
* Retrieve the given annotation's attributes as an {@link AnnotationAttributes} map.
* This method provides fully recursive annotation reading capabilities on par with
* the reflection-based {@link org.springframework.core.type.StandardAnnotationMetadata}.
* @param annotatedElement the element that is annotated with the supplied annotation;
* may be {@code null} if unknown
* @param annotation the annotation to retrieve the attributes for
* @param classValuesAsString whether to convert Class references into Strings (for
* compatibility with {@link org.springframework.core.type.AnnotationMetadata})
* or to preserve them as Class references
* @param nestedAnnotationsAsMap whether to convert nested annotations into
* {@link AnnotationAttributes} maps (for compatibility with
* {@link org.springframework.core.type.AnnotationMetadata}) or to preserve them as
* {@code Annotation} instances
* @return the annotation attributes (a specialized Map) with attribute names as keys
* and corresponding attribute values as values; never {@code null}
* @since 4.2
*/
public static AnnotationAttributes getAnnotationAttributes(AnnotatedElement annotatedElement,
Annotation annotation, boolean classValuesAsString, boolean nestedAnnotationsAsMap) {
return getAnnotationAttributes(annotatedElement, annotation, classValuesAsString, nestedAnnotationsAsMap, false);
}
/**
* Retrieve the given annotation's attributes as an {@link AnnotationAttributes} map.
*
* This method provides fully recursive annotation reading capabilities on par with
* the reflection-based {@link org.springframework.core.type.StandardAnnotationMetadata}.
*
* NOTE: This variant of {@code getAnnotationAttributes()} is
* only intended for use within the framework. Specifically, the {@code mergeMode} flag
* can be set to {@code true} in order to support processing of attribute aliases while
* merging attributes within an annotation hierarchy. When running in merge mode,
* the following special rules apply:
* Nested annotations will be
* {@linkplain #synthesizeAnnotation(Annotation, AnnotatedElement) synthesized}.
* @param annotatedElement the element that is annotated, used for contextual
* logging; may be {@code null} if unknown
* @param value the annotation attribute value
* @param classValuesAsString whether to convert Class references into Strings (for
* compatibility with {@link org.springframework.core.type.AnnotationMetadata})
* or to preserve them as Class references
* @param nestedAnnotationsAsMap whether to convert nested annotations into
* {@link AnnotationAttributes} maps (for compatibility with
* {@link org.springframework.core.type.AnnotationMetadata}) or to preserve them as
* {@code Annotation} instances
* @return the adapted value, or the original value if no adaptation is needed
*/
static Object adaptValue(AnnotatedElement annotatedElement, Object value, boolean classValuesAsString,
boolean nestedAnnotationsAsMap) {
if (classValuesAsString) {
if (value instanceof Class) {
return ((Class) value).getName();
}
else if (value instanceof Class[]) {
Class[] clazzArray = (Class[]) value;
String[] classNames = new String[clazzArray.length];
for (int i = 0; i < clazzArray.length; i++) {
classNames[i] = clazzArray[i].getName();
}
return classNames;
}
}
if (value instanceof Annotation) {
Annotation annotation = (Annotation) value;
if (nestedAnnotationsAsMap) {
return getAnnotationAttributes(annotatedElement, annotation, classValuesAsString,
nestedAnnotationsAsMap);
}
else {
return synthesizeAnnotation(annotation, annotatedElement);
}
}
if (value instanceof Annotation[]) {
Annotation[] annotations = (Annotation[]) value;
if (nestedAnnotationsAsMap) {
AnnotationAttributes[] mappedAnnotations = new AnnotationAttributes[annotations.length];
for (int i = 0; i < annotations.length; i++) {
mappedAnnotations[i] = getAnnotationAttributes(annotatedElement, annotations[i],
classValuesAsString, nestedAnnotationsAsMap);
}
return mappedAnnotations;
}
else {
return synthesizeAnnotationArray(annotations, annotatedElement);
}
}
// Fallback
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) {
if (annotation == null || !StringUtils.hasText(attributeName)) {
return null;
}
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) {
if (annotation == null) {
return null;
}
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 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 annotationType, String attributeName) {
if (annotationType == null || !StringUtils.hasText(attributeName)) {
return null;
}
try {
return annotationType.getDeclaredMethod(attributeName).getDefaultValue();
}
catch (Exception ex) {
return null;
}
}
/**
* Synthesize an annotation from the supplied {@code annotation}
* by wrapping it in a dynamic proxy that transparently enforces
* attribute alias semantics for annotation attributes that are
* annotated with {@link AliasFor @AliasFor}.
*
* @param annotation the annotation to synthesize
* @return the synthesized annotation, if the supplied annotation is
* synthesizable; {@code null} if the supplied annotation is
* {@code null}; otherwise, the supplied annotation unmodified
* @throws AnnotationConfigurationException if invalid configuration of
* {@code @AliasFor} is detected
* @since 4.2
* @see #synthesizeAnnotation(Annotation, AnnotatedElement)
*/
static A synthesizeAnnotation(A annotation) {
return synthesizeAnnotation(annotation, null);
}
/**
* Synthesize an annotation from the supplied {@code annotation}
* by wrapping it in a dynamic proxy that transparently enforces
* attribute alias semantics for annotation attributes that are
* annotated with {@link AliasFor @AliasFor}.
*
* @param annotation the annotation to synthesize
* @param annotatedElement the element that is annotated with the supplied
* annotation; may be {@code null} if unknown
* @return the synthesized annotation if the supplied annotation is
* synthesizable; {@code null} if the supplied annotation is
* {@code null}; otherwise the supplied annotation unmodified
* @throws AnnotationConfigurationException if invalid configuration of
* {@code @AliasFor} is detected
* @since 4.2
* @see #synthesizeAnnotation(Map, Class, AnnotatedElement)
*/
@SuppressWarnings("unchecked")
public static A synthesizeAnnotation(A annotation, AnnotatedElement annotatedElement) {
if (annotation == null) {
return null;
}
if (annotation instanceof SynthesizedAnnotation) {
return annotation;
}
Class annotationType = annotation.annotationType();
if (!isSynthesizable(annotationType)) {
return annotation;
}
AnnotationAttributeExtractor attributeExtractor = new DefaultAnnotationAttributeExtractor(annotation,
annotatedElement);
InvocationHandler handler = new SynthesizedAnnotationInvocationHandler(attributeExtractor);
A synthesizedAnnotation = (A) Proxy.newProxyInstance(ClassUtils.getDefaultClassLoader(), new Class[] {
(Class) annotationType, SynthesizedAnnotation.class }, handler);
return synthesizedAnnotation;
}
/**
* Synthesize an annotation from the supplied map of annotation
* attributes by wrapping the map in a dynamic proxy that implements an
* annotation of the specified {@code annotationType} and transparently
* enforces attribute alias semantics for annotation attributes
* that are annotated with {@link AliasFor @AliasFor}.
* The supplied map must contain a key-value pair for every attribute
* defined in the supplied {@code annotationType} that is not aliased or
* does not have a default value.
* Note that {@link AnnotationAttributes} is a specialized type of
* {@link Map} that is an ideal candidate for this method's
* {@code attributes} argument.
*
* @param attributes the map of annotation attributes to synthesize
* @param annotationType the type of annotation to synthesize; never {@code null}
* @param annotatedElement the element that is annotated with the annotation
* corresponding to the supplied attributes; may be {@code null} if unknown
* @return the synthesized annotation, or {@code null} if the supplied attributes
* map is {@code null}
* @throws IllegalArgumentException if a required attribute is missing or if an
* attribute is not of the correct type
* @throws AnnotationConfigurationException if invalid configuration of
* {@code @AliasFor} is detected
* @since 4.2
* @see #synthesizeAnnotation(Annotation, AnnotatedElement)
*/
@SuppressWarnings("unchecked")
public static A synthesizeAnnotation(Map The map is keyed by attribute name with each value representing
* the name of the aliased attribute. For each entry {@code [x, y]} in
* the map there will be a corresponding {@code [y, x]} entry in the map.
*
* An empty return value implies that the annotation does not declare
* any attribute aliases.
*
* @param annotationType the annotation type to find attribute aliases in
* @return a map containing attribute alias pairs; never {@code null}
* @since 4.2
*/
static Map Specifically, an annotation is synthesizable if it declares
* any attributes that are configured as aliased pairs via
* {@link AliasFor @AliasFor} or if any nested annotations used by the
* annotation declare such aliased pairs.
*
* @since 4.2
* @see SynthesizedAnnotation
* @see SynthesizedAnnotationInvocationHandler
*/
@SuppressWarnings("unchecked")
private static boolean isSynthesizable(Class annotationType) {
Boolean synthesizable = synthesizableCache.get(annotationType);
if (synthesizable != null) {
return synthesizable.booleanValue();
}
synthesizable = Boolean.FALSE;
for (Method attribute : getAttributeMethods(annotationType)) {
if (getAliasedAttributeName(attribute) != null) {
synthesizable = Boolean.TRUE;
break;
}
Class returnType = attribute.getReturnType();
if (Annotation[].class.isAssignableFrom(returnType)) {
Class nestedAnnotationType = (Class) returnType.getComponentType();
if (isSynthesizable(nestedAnnotationType)) {
synthesizable = Boolean.TRUE;
break;
}
}
else if (Annotation.class.isAssignableFrom(returnType)) {
Class nestedAnnotationType = (Class) returnType;
if (isSynthesizable(nestedAnnotationType)) {
synthesizable = Boolean.TRUE;
break;
}
}
}
synthesizableCache.put(annotationType, synthesizable);
return synthesizable.booleanValue();
}
/**
* Get the name of the aliased attribute configured via
* {@link AliasFor @AliasFor} on the supplied annotation {@code attribute}.
*
* This method does not resolve aliases in other annotations. In
* other words, if {@code @AliasFor} is present on the supplied
* {@code attribute} but {@linkplain AliasFor#annotation references an
* annotation} other than {@link Annotation}, this method will return
* {@code null} immediately.
*
* @param attribute the attribute to find an alias for
* @return the name of the aliased attribute, or {@code null} if not found
* @throws IllegalArgumentException if the supplied attribute method is
* not from an annotation, or if the supplied target type is {@link Annotation}
* @throws AnnotationConfigurationException if invalid configuration of
* {@code @AliasFor} is detected
* @since 4.2
* @see #getAliasedAttributeName(Method, Class)
*/
static String getAliasedAttributeName(Method attribute) {
return getAliasedAttributeName(attribute, null);
}
/**
* Get the name of the aliased attribute configured via
* {@link AliasFor @AliasFor} on the supplied annotation {@code attribute}.
*
* @param attribute the attribute to find an alias for
* @param targetAnnotationType the type of annotation in which the
* aliased attribute is allowed to be declared; {@code null} implies
* within the same annotation
* @return the name of the aliased attribute, or {@code null} if not found
* @throws IllegalArgumentException if the supplied attribute method is
* not from an annotation, or if the supplied target type is {@link Annotation}
* @throws AnnotationConfigurationException if invalid configuration of
* {@code @AliasFor} is detected
* @since 4.2
*/
@SuppressWarnings("unchecked")
static String getAliasedAttributeName(Method attribute, Class targetAnnotationType) {
Class declaringClass = attribute.getDeclaringClass();
Assert.isTrue(declaringClass.isAnnotation(), "attribute method must be from an annotation");
Assert.isTrue(!Annotation.class.equals(targetAnnotationType),
"targetAnnotationType must not be java.lang.annotation.Annotation");
AliasFor aliasFor = attribute.getAnnotation(AliasFor.class);
// Nothing to check
if (aliasFor == null) {
return null;
}
Class sourceAnnotationType = (Class) declaringClass;
Class aliasedAnnotationType = aliasFor.annotation();
boolean searchWithinSameAnnotation = (targetAnnotationType == null);
boolean sameTargetDeclared = (sourceAnnotationType.equals(aliasedAnnotationType) || Annotation.class.equals(aliasedAnnotationType));
// Wrong search scope?
if (searchWithinSameAnnotation && !sameTargetDeclared) {
return null;
}
String attributeName = attribute.getName();
String aliasedAttributeName = aliasFor.attribute();
if (!StringUtils.hasText(aliasedAttributeName)) {
String msg = String.format(
"@AliasFor declaration on attribute [%s] in annotation [%s] is missing required 'attribute' value.",
attributeName, sourceAnnotationType.getName());
throw new AnnotationConfigurationException(msg);
}
if (sameTargetDeclared) {
aliasedAnnotationType = sourceAnnotationType;
}
Method aliasedAttribute = null;
try {
aliasedAttribute = aliasedAnnotationType.getDeclaredMethod(aliasedAttributeName);
}
catch (NoSuchMethodException e) {
String msg = String.format(
"Attribute [%s] in annotation [%s] is declared as an @AliasFor nonexistent attribute [%s] in annotation [%s].",
attributeName, sourceAnnotationType.getName(), aliasedAttributeName, aliasedAnnotationType.getName());
throw new AnnotationConfigurationException(msg, e);
}
if (sameTargetDeclared) {
AliasFor mirrorAliasFor = aliasedAttribute.getAnnotation(AliasFor.class);
if (mirrorAliasFor == null) {
String msg = String.format("Attribute [%s] in annotation [%s] must be declared as an @AliasFor [%s].",
aliasedAttributeName, sourceAnnotationType.getName(), attributeName);
throw new AnnotationConfigurationException(msg);
}
String mirrorAliasedAttributeName = mirrorAliasFor.attribute();
if (!attributeName.equals(mirrorAliasedAttributeName)) {
String msg = String.format(
"Attribute [%s] in annotation [%s] must be declared as an @AliasFor [%s], not [%s].",
aliasedAttributeName, sourceAnnotationType.getName(), attributeName, mirrorAliasedAttributeName);
throw new AnnotationConfigurationException(msg);
}
}
Class returnType = attribute.getReturnType();
Class aliasedReturnType = aliasedAttribute.getReturnType();
if (!returnType.equals(aliasedReturnType)) {
String msg = String.format("Misconfigured aliases: attribute [%s] in annotation [%s] "
+ "and attribute [%s] in annotation [%s] must declare the same return type.", attributeName,
sourceAnnotationType.getName(), aliasedAttributeName, aliasedAnnotationType.getName());
throw new AnnotationConfigurationException(msg);
}
if (sameTargetDeclared) {
Object defaultValue = attribute.getDefaultValue();
Object aliasedDefaultValue = aliasedAttribute.getDefaultValue();
if ((defaultValue == null) || (aliasedDefaultValue == null)) {
String msg = String.format("Misconfigured aliases: attribute [%s] in annotation [%s] "
+ "and attribute [%s] in annotation [%s] must declare default values.", attributeName,
sourceAnnotationType.getName(), aliasedAttributeName, aliasedAnnotationType.getName());
throw new AnnotationConfigurationException(msg);
}
if (!ObjectUtils.nullSafeEquals(defaultValue, aliasedDefaultValue)) {
String msg = String.format("Misconfigured aliases: attribute [%s] in annotation [%s] "
+ "and attribute [%s] in annotation [%s] must declare the same default value.", attributeName,
sourceAnnotationType.getName(), aliasedAttributeName, aliasedAnnotationType.getName());
throw new AnnotationConfigurationException(msg);
}
}
return aliasedAttributeName;
}
/**
* Get all methods declared in the supplied {@code annotationType} that
* match Java's requirements for annotation attributes.
*
* All methods in the returned list will be
* {@linkplain ReflectionUtils#makeAccessible(Method) made accessible}.
*
* @param annotationType the type in which to search for attribute methods;
* never {@code null}
* @return all annotation attribute methods in the specified annotation
* type; never {@code null}, though potentially empty
* @since 4.2
*/
static List Specifically, this method enforces attribute alias semantics
* for annotation attributes that are annotated with {@link AliasFor @AliasFor}
* and replaces {@linkplain #DEFAULT_VALUE_PLACEHOLDER placeholders} with their
* original default values.
*
* @param element the element that is annotated with an annotation or
* annotation hierarchy from which the supplied attributes were created;
* may be {@code null} if unknown
* @param attributes the annotation attributes to post-process
* @param classValuesAsString whether to convert Class references into Strings (for
* compatibility with {@link org.springframework.core.type.AnnotationMetadata})
* or to preserve them as Class references
* @param nestedAnnotationsAsMap whether to convert nested annotations into
* {@link AnnotationAttributes} maps (for compatibility with
* {@link org.springframework.core.type.AnnotationMetadata}) or to preserve them as
* {@code Annotation} instances
* @since 4.2
* @see #getAnnotationAttributes(AnnotatedElement, Annotation, boolean, boolean, boolean)
* @see #DEFAULT_VALUE_PLACEHOLDER
* @see #getDefaultValue(Class, String)
*/
static void postProcessAnnotationAttributes(AnnotatedElement element, AnnotationAttributes attributes,
boolean classValuesAsString, boolean nestedAnnotationsAsMap) {
// Abort?
if (attributes == null) {
return;
}
Class annotationType = attributes.annotationType();
// Validate @AliasFor configuration
Map If the supplied throwable is an {@link AnnotationConfigurationException},
* it will be cast to an {@code AnnotationConfigurationException} and thrown,
* allowing it to propagate to the caller.
* Otherwise, this method does nothing.
* @param t the throwable to inspect
* @since 4.2
*/
static void rethrowAnnotationConfigurationException(Throwable t) {
if (t instanceof AnnotationConfigurationException) {
throw (AnnotationConfigurationException) t;
}
}
/**
* Handle the supplied annotation introspection exception.
* If the supplied exception is an {@link AnnotationConfigurationException},
* it will simply be thrown, allowing it to propagate to the caller, and
* nothing will be logged.
* Otherwise, this method logs an introspection failure (in particular
* {@code TypeNotPresentExceptions}) — before moving on, pretending
* there were no annotations on this specific element.
* @param element the element that we tried to introspect annotations on
* @param ex the exception that we encountered
* @see #rethrowAnnotationConfigurationException
*/
static void handleIntrospectionFailure(AnnotatedElement element, Exception ex) {
rethrowAnnotationConfigurationException(ex);
Log loggerToUse = logger;
if (loggerToUse == null) {
loggerToUse = LogFactory.getLog(AnnotationUtils.class);
logger = loggerToUse;
}
if (element instanceof Class && Annotation.class.isAssignableFrom((Class) element)) {
// Meta-annotation lookup on an annotation type
if (logger.isDebugEnabled()) {
logger.debug("Failed to introspect meta-annotations on [" + element + "]: " + ex);
}
}
else {
// Direct annotation lookup on regular Class, Method, Field
if (loggerToUse.isInfoEnabled()) {
logger.info("Failed to introspect annotations on [" + element + "]: " + ex);
}
}
}
/**
* Cache key for the AnnotatedElement cache.
*/
private static class AnnotationCacheKey {
private final AnnotatedElement element;
private final Class annotationType;
public AnnotationCacheKey(AnnotatedElement element, Class 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 containerAnnotationType;
private final Class annotationType;
private final Set
*
*
*
*
* @param annotatedElement the element that is annotated with the supplied annotation;
* may be {@code null} if unknown
* @param annotation the annotation to retrieve the attributes for
* @param classValuesAsString whether to convert Class references into Strings (for
* compatibility with {@link org.springframework.core.type.AnnotationMetadata})
* or to preserve them as Class references
* @param nestedAnnotationsAsMap whether to convert nested annotations into
* {@link AnnotationAttributes} maps (for compatibility with
* {@link org.springframework.core.type.AnnotationMetadata}) or to preserve them as
* {@code Annotation} instances
* @param mergeMode whether the annotation attributes should be created
* using merge mode
* @return the annotation attributes (a specialized Map) with attribute names as keys
* and corresponding attribute values as values; never {@code null}
* @since 4.2
* @see #postProcessAnnotationAttributes
*/
static AnnotationAttributes getAnnotationAttributes(AnnotatedElement annotatedElement, Annotation annotation,
boolean classValuesAsString, boolean nestedAnnotationsAsMap, boolean mergeMode) {
if (!mergeMode) {
annotation = synthesizeAnnotation(annotation, annotatedElement);
}
Class annotationType = annotation.annotationType();
AnnotationAttributes attrs = new AnnotationAttributes(annotationType);
for (Method method : getAttributeMethods(annotationType)) {
try {
Object value = method.invoke(annotation);
Object defaultValue = method.getDefaultValue();
if (mergeMode && (defaultValue != null)) {
if (ObjectUtils.nullSafeEquals(value, defaultValue)) {
value = DEFAULT_VALUE_PLACEHOLDER;
}
}
attrs.put(method.getName(),
adaptValue(annotatedElement, value, classValuesAsString, nestedAnnotationsAsMap));
}
catch (Exception ex) {
if (ex instanceof InvocationTargetException) {
Throwable targetException = ((InvocationTargetException) ex).getTargetException();
rethrowAnnotationConfigurationException(targetException);
}
throw new IllegalStateException("Could not obtain annotation attribute value for " + method, ex);
}
}
return attrs;
}
/**
* Adapt the given value according to the given class and nested annotation settings.
*