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* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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
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* Unless required by applicable law or agreed to in writing,
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* KIND, either express or implied. See the License for the
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package org.apache.cayenne.jpa.conf;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import javax.persistence.PostLoad;
import javax.persistence.PostPersist;
import javax.persistence.PostRemove;
import javax.persistence.PostUpdate;
import javax.persistence.PrePersist;
import javax.persistence.PreRemove;
import javax.persistence.PreUpdate;
import org.apache.cayenne.jpa.map.JpaEntityListener;
import org.apache.cayenne.jpa.map.JpaLifecycleCallback;
/**
* Loads annotations from the entity listener class. Only deals with non-entity formats of
* annotation methods.
* <h3>JPA Spec, 3.4.1:</h3>
* <p>
* Callback methods defined on an entity class have the following signature: <em>void
* <METHOD>()</em>
* Callback methods defined on an entity listener class have the following signature:
* <em>void <METHOD>(Object)</em> The Object argument is the entity instance for which
* the callback method is invoked. It maybe declared as the actual entity type. The
* callback methods can have public, private, protected, or package level access, but must
* not be static or final.
* </p>
*
*/
public class EntityListenerAnnotationLoader {
/**
* Returns a listener methods descriptor for the annotated listener, or null if none
* of the class methods are properly annotated.
*/
public JpaEntityListener getEntityListener(Class<?> listenerClass) {
JpaEntityListener listener = new JpaEntityListener();
boolean hasAnnotations = false;
Method[] methods = listenerClass.getDeclaredMethods();
for (int i = 0; i < methods.length; i++) {
if (isValidListenerMethod(methods[i])) {
if (processAnnotations(methods[i], listener)) {
hasAnnotations = true;
}
}
}
if (hasAnnotations) {
listener.setClassName(listenerClass.getName());
return listener;
}
return null;
}
/**
* Checks that the method signature is one of a valid listener method,
* <em>void METHOD(Object)</em>.
*/
protected boolean isValidListenerMethod(Method m) {
int modifiers = m.getModifiers();
if (Modifier.isStatic(modifiers) || Modifier.isFinal(modifiers)) {
return false;
}
if (!Void.TYPE.equals(m.getReturnType())) {
return false;
}
Class<?>[] params = m.getParameterTypes();
if (params.length != 1 || !Object.class.equals(params[0])) {
return false;
}
return true;
}
protected boolean processAnnotations(Method method, JpaEntityListener listener) {
boolean hasListenerAnnotations = false;
if (method.isAnnotationPresent(PrePersist.class)) {
listener.setPrePersist(new JpaLifecycleCallback(method.getName()));
hasListenerAnnotations = true;
}
if (method.isAnnotationPresent(PostPersist.class)) {
listener.setPostPersist(new JpaLifecycleCallback(method.getName()));
hasListenerAnnotations = true;
}
if (method.isAnnotationPresent(PreRemove.class)) {
listener.setPreRemove(new JpaLifecycleCallback(method.getName()));
hasListenerAnnotations = true;
}
if (method.isAnnotationPresent(PostRemove.class)) {
listener.setPostRemove(new JpaLifecycleCallback(method.getName()));
hasListenerAnnotations = true;
}
if (method.isAnnotationPresent(PreUpdate.class)) {
listener.setPreUpdate(new JpaLifecycleCallback(method.getName()));
hasListenerAnnotations = true;
}
if (method.isAnnotationPresent(PostUpdate.class)) {
listener.setPostUpdate(new JpaLifecycleCallback(method.getName()));
hasListenerAnnotations = true;
}
if (method.isAnnotationPresent(PostLoad.class)) {
listener.setPostLoad(new JpaLifecycleCallback(method.getName()));
hasListenerAnnotations = true;
}
return hasListenerAnnotations;
}
}