001// Copyright 2006, 2007, 2008, 2011 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007// http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.internal.event;
016
017import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
018import org.apache.tapestry5.services.InvalidationEventHub;
019import org.apache.tapestry5.services.InvalidationListener;
020
021import java.util.List;
022
023/**
024 * Base implementation class for classes (especially services) that need to manage a list of
025 * {@link org.apache.tapestry5.services.InvalidationListener}s.
026 */
027public class InvalidationEventHubImpl implements InvalidationEventHub
028{
029    private final List<InvalidationListener> listeners;
030
031    protected InvalidationEventHubImpl(boolean productionMode)
032    {
033        if (productionMode)
034        {
035            listeners = null;
036        } else
037        {
038            listeners = CollectionFactory.newThreadSafeList();
039        }
040    }
041
042    /**
043     * Notifies all {@link InvalidationListener listener}s.
044     */
045    protected final void fireInvalidationEvent()
046    {
047        if (listeners == null)
048        {
049            return;
050        }
051
052        for (InvalidationListener listener : listeners)
053        {
054            listener.objectWasInvalidated();
055        }
056    }
057
058    public final void addInvalidationListener(InvalidationListener listener)
059    {
060        if (listeners != null)
061        {
062            listeners.add(listener);
063        }
064    }
065}