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* to you under the Apache License, Version 2.0 (the
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package org.apache.cayenne.intercept;
import java.util.List;
import org.apache.cayenne.DataChannel;
import org.apache.cayenne.LifecycleListener;
import org.apache.cayenne.ObjectContext;
import org.apache.cayenne.QueryResponse;
import org.apache.cayenne.graph.GraphDiff;
import org.apache.cayenne.graph.GraphManager;
import org.apache.cayenne.query.Query;
import org.apache.cayenne.reflect.LifecycleCallbackRegistry;
/**
* Implements JPA-compliant "PreUpdate", "PostUpdate", "PostPersist", "PostRemove",
* "PostLoad" callbacks for the DataChannel operations. <p/>Depending on how callbacks are
* registered, they are invoked either on persistent object instances directly or on an
* instance of an arbitrary listener class. Signature of a callback method of a persistent
* object is <code>"void method()"</code>, while for a non-persistent listener it is
* <code>"void method(Object)"</code>. <p/>Note that this interceptor does not apply
* "PreRemove" and "PrePersist" callbacks during "onSync", assuming that a child
* ObjectContext did that already. It is often used in conjunction with
* {@link ObjectContextCallbackInterceptor} that adds those callbacks.
*
* @see ObjectContextCallbackInterceptor
* @since 3.0
* @author Andrus Adamchik
*/
public class DataChannelCallbackInterceptor extends DataChannelDecorator {
protected LifecycleCallbackRegistry callbackRegistry;
protected boolean contextCallbacksEnabled;
public void setChannel(DataChannel channel) {
this.channel = channel;
callbackRegistry = (channel != null)
? getEntityResolver().getCallbackRegistry()
: null;
}
protected boolean isEmpty() {
if (!(callbackRegistry.isEmpty(LifecycleListener.PRE_UPDATE)
&& callbackRegistry.isEmpty(LifecycleListener.POST_PERSIST)
&& callbackRegistry.isEmpty(LifecycleListener.POST_REMOVE)
&& callbackRegistry.isEmpty(LifecycleListener.POST_UPDATE) && callbackRegistry
.isEmpty(LifecycleListener.POST_LOAD))) {
return false;
}
return contextCallbacksEnabled ? callbackRegistry.isEmpty(LifecycleListener.PRE_REMOVE)
&& callbackRegistry.isEmpty(LifecycleListener.PRE_PERSIST) : true;
}
public QueryResponse onQuery(ObjectContext originatingContext, Query query) {
QueryResponse response = channel.onQuery(originatingContext, query);
// TODO: andrus, 9/21/2006 - this method incorrectly calls "postLoad" when query
// refresh flag is set to false and object is already there.
if (!callbackRegistry.isEmpty(LifecycleListener.POST_LOAD)) {
List list = response.firstList();
if (list != null
&& !list.isEmpty()
&& !(query.getMetaData(channel.getEntityResolver()))
.isFetchingDataRows()) {
callbackRegistry.performCallbacks(LifecycleListener.POST_LOAD, list);
}
}
return response;
}
public GraphDiff onSync(
ObjectContext originatingContext,
GraphDiff changes,
int syncType) {
if (isEmpty()) {
return channel.onSync(originatingContext, changes, syncType);
}
SyncCallbackProcessor processor = createSyncProcessor(originatingContext
.getGraphManager(), changes);
processor.applyPreCommit(syncType);
GraphDiff parentDiff = channel.onSync(originatingContext, changes, syncType);
processor.applyPostCommit(syncType);
return parentDiff;
}
SyncCallbackProcessor createSyncProcessor(GraphManager graphManager, GraphDiff changes) {
return new SyncCallbackProcessor(this, graphManager, changes);
}
/**
* Returns whether "PrePersist" and "PreRemove" callbacks should be executed during
* sync. By default this is false, as they are executed by the parent ObjectContext.
* This can be changed by calling {@link #setContextCallbacksEnabled(boolean)}.
*/
public boolean isContextCallbacksEnabled() {
return contextCallbacksEnabled;
}
public void setContextCallbacksEnabled(boolean contextCallbacksEnabled) {
this.contextCallbacksEnabled = contextCallbacksEnabled;
}
public LifecycleCallbackRegistry getCallbackRegistry() {
return callbackRegistry;
}
}