/*
* Copyright 2002-2006 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.aop.aspectj.annotation;
import java.lang.reflect.Method;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.util.ObjectUtils;
/**
* Add a DeclareParents field in concrete subclasses, to identify
* the type pattern to apply the introduction to.
*
* @author Rod Johnson
* @since 2.0
*/
@Aspect
public abstract class AbstractMakeModifiable {
public interface MutableModifable extends Modifiable {
void markDirty();
}
public static class ModifiableImpl implements MutableModifable {
private boolean modified;
public void acceptChanges() {
modified = false;
}
public boolean isModified() {
return modified;
}
public void markDirty() {
this.modified = true;
}
}
@Before(value="execution(void set*(*)) && this(modifiable) && args(newValue)",
argNames="modifiable,newValue")
public void recordModificationIfSetterArgumentDiffersFromOldValue(JoinPoint jp,
MutableModifable mixin, Object newValue) {
/*
* We use the mixin to check and, if necessary, change,
* modification status. We need the JoinPoint to get the
* setter method. We use newValue for comparison.
* We try to invoke the getter if possible.
*/
if (mixin.isModified()) {
// Already changed, don't need to change again
//System.out.println("changed");
return;
}
// Find the current raw value, by invoking the corresponding setter
Method correspondingGetter = getGetterFromSetter(((MethodSignature) jp.getSignature()).getMethod());
boolean modified = true;
if (correspondingGetter != null) {
try {
Object oldValue = correspondingGetter.invoke(jp.getTarget());
//System.out.println("Old value=" + oldValue + "; new=" + newValue);
modified = !ObjectUtils.nullSafeEquals(oldValue, newValue);
}
catch (Exception ex) {
ex.printStackTrace();
// Don't sweat on exceptions; assume value was modified
}
}
else {
//System.out.println("cannot get getter for " + jp);
}
if (modified) {
mixin.markDirty();
}
}
private Method getGetterFromSetter(Method setter) {
String getterName = setter.getName().replaceFirst("set", "get");
try {
return setter.getDeclaringClass().getMethod(getterName, (Class[]) null);
}
catch (NoSuchMethodException ex) {
// must be write only
return null;
}
}
}