/*****************************************************************
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* 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
*
* 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.apache.cayenne;
import org.apache.cayenne.reflect.ArcProperty;
import org.apache.cayenne.reflect.AttributeProperty;
import org.apache.cayenne.reflect.PropertyVisitor;
import org.apache.cayenne.reflect.ToManyProperty;
import org.apache.cayenne.reflect.ToOneProperty;
import org.apache.cayenne.util.ObjectContextGraphAction;
/**
* An action object that processes graph change calls from Persistent object. It handles
* GraphManager notifications and bi-directional graph consistency.
*
* @since 1.2
* @author Andrus Adamchik
*/
class CayenneContextGraphAction extends ObjectContextGraphAction {
static final ThreadLocal<Boolean> arcChangeInProcess = new ThreadLocal<Boolean>() {
@Override
protected synchronized Boolean initialValue() {
return Boolean.FALSE;
}
};
CayenneContextGraphAction(ObjectContext context) {
super(context);
}
@Override
protected void handleArcPropertyChange(
Persistent object,
ArcProperty property,
Object oldValue,
Object newValue) {
if (isArchChangeInProcess()) {
return;
}
// prevent reverse actions down the stack
setArcChangeInProcess(true);
try {
if (oldValue instanceof Persistent) {
context.getGraphManager().arcDeleted(
object.getObjectId(),
((Persistent) oldValue).getObjectId(),
property.getName());
unsetReverse(property, object, (Persistent) oldValue);
markAsDirty(object);
}
if (newValue instanceof Persistent) {
context.getGraphManager().arcCreated(
object.getObjectId(),
((Persistent) newValue).getObjectId(),
property.getName());
setReverse(property, object, (Persistent) newValue);
markAsDirty(object);
}
}
finally {
setArcChangeInProcess(false);
}
}
@Override
protected void handleSimplePropertyChange(
Persistent object,
String propertyName,
Object oldValue,
Object newValue) {
context.getGraphManager().nodePropertyChanged(
object.getObjectId(),
propertyName,
oldValue,
newValue);
markAsDirty(object);
}
/**
* Returns true if the current thread is in the process of changing the arc property.
* This method is used to prevent cycles when setting reverse relationships.
*/
boolean isArchChangeInProcess() {
return arcChangeInProcess.get();
}
/**
* Sets the flag indicating whether the current thread is in the process of changing
* the arc property. This method is used to prevent cycles when setting reverse
* relationships.
*/
void setArcChangeInProcess(boolean flag) {
arcChangeInProcess.set(flag);
}
private void setReverse(
ArcProperty property,
final Persistent sourceObject,
final Persistent targetObject) {
ArcProperty reverseArc = property.getComplimentaryReverseArc();
if (reverseArc != null) {
reverseArc.visit(new PropertyVisitor() {
public boolean visitToMany(ToManyProperty property) {
property.addTarget(targetObject, sourceObject, false);
return false;
}
public boolean visitToOne(ToOneProperty property) {
property.setTarget(targetObject, sourceObject, false);
return false;
}
public boolean visitAttribute(AttributeProperty property) {
return false;
}
});
context.getGraphManager().arcCreated(
targetObject.getObjectId(),
sourceObject.getObjectId(),
reverseArc.getName());
markAsDirty(targetObject);
}
}
private void unsetReverse(
ArcProperty property,
Persistent sourceObject,
Persistent targetObject) {
ArcProperty reverseArc = property.getComplimentaryReverseArc();
if (reverseArc != null) {
reverseArc.writePropertyDirectly(targetObject, sourceObject, null);
context.getGraphManager().arcDeleted(
targetObject.getObjectId(),
sourceObject.getObjectId(),
reverseArc.getName());
markAsDirty(targetObject);
}
}
}