org.springframework.core.annotation.AnnotationUtils Maven / Gradle / Ivy
/*
* Copyright 2002-2007 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.Method;
import org.springframework.core.BridgeMethodResolver;
/**
* 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 instead of the plain annotation lookup methods in the JDK.
* You can still explicitly choose between lookup on the given class level only
* ({@link #getAnnotation}) and lookup in the entire inheritance hierarchy of
* the given method ({@link #findAnnotation}).
*
* @author Rod Johnson
* @author Rob Harrop
* @author Juergen Hoeller
* @since 2.0
* @see java.lang.reflect.Method#getAnnotations()
* @see java.lang.reflect.Method#getAnnotation(Class)
*/
public abstract class AnnotationUtils {
/**
* Get all {@link Annotation Annotations} from the supplied {@link Method}.
*
Correctly handles bridge {@link Method Methods} generated by the compiler.
* @param method the method to look for annotations on
* @return the annotations found
* @see org.springframework.core.BridgeMethodResolver#findBridgedMethod(Method)
*/
public static Annotation[] getAnnotations(Method method) {
return BridgeMethodResolver.findBridgedMethod(method).getAnnotations();
}
/**
* Get a single {@link Annotation} of 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 class to look for
* @return the annotations found
* @see org.springframework.core.BridgeMethodResolver#findBridgedMethod(Method)
*/
public static A getAnnotation(Method method, Class annotationType) {
return BridgeMethodResolver.findBridgedMethod(method).getAnnotation(annotationType);
}
/**
* Get a single {@link Annotation} of annotationType from the
* supplied {@link Method}, traversing its super methods if no annotation
* can be found on the given 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 class to look for
* @return the annotation of the given type found, or null
*/
public static A findAnnotation(Method method, Class annotationType) {
if (!annotationType.isAnnotation()) {
throw new IllegalArgumentException(annotationType + " is not an annotation");
}
A annotation = getAnnotation(method, annotationType);
Class cl = method.getDeclaringClass();
while (annotation == null) {
cl = cl.getSuperclass();
if (cl == null || cl.equals(Object.class)) {
break;
}
try {
method = cl.getDeclaredMethod(method.getName(), method.getParameterTypes());
annotation = getAnnotation(method, annotationType);
}
catch (NoSuchMethodException ex) {
// We're done...
}
}
return annotation;
}
}