001// Copyright 2006, 2007, 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.ioc.internal.services;
016
017import org.apache.tapestry5.func.F;
018import org.apache.tapestry5.func.Worker;
019import org.apache.tapestry5.ioc.internal.util.OneShotLock;
020import org.apache.tapestry5.ioc.services.RegistryShutdownHub;
021import org.apache.tapestry5.ioc.services.RegistryShutdownListener;
022import org.slf4j.Logger;
023
024import java.util.List;
025
026import static org.apache.tapestry5.ioc.internal.util.CollectionFactory.newThreadSafeList;
027
028public class RegistryShutdownHubImpl implements RegistryShutdownHub
029{
030    private final OneShotLock lock = new OneShotLock();
031
032    private final Logger logger;
033
034    private final List<Runnable> listeners = newThreadSafeList();
035
036    private final List<Runnable> preListeners = newThreadSafeList();
037
038    public RegistryShutdownHubImpl(Logger logger)
039    {
040        this.logger = logger;
041    }
042
043    public void addRegistryShutdownListener(final RegistryShutdownListener listener)
044    {
045        assert listener != null;
046
047        addRegistryShutdownListener(new Runnable()
048        {
049            public void run()
050            {
051                listener.registryDidShutdown();
052            }
053        });
054    }
055
056    public void addRegistryShutdownListener(Runnable listener)
057    {
058        assert listener != null;
059
060        lock.check();
061
062        listeners.add(listener);
063    }
064
065    public void addRegistryWillShutdownListener(Runnable listener)
066    {
067        assert listener != null;
068
069        lock.check();
070
071        preListeners.add(listener);
072    }
073
074    /**
075     * Fires the {@link RegistryShutdownListener#registryDidShutdown()} method on each listener. At the end, all the
076     * listeners are discarded.
077     */
078    public void fireRegistryDidShutdown()
079    {
080        lock.lock();
081
082        F.flow(preListeners).concat(listeners).each(new Worker<Runnable>()
083        {
084            public void work(Runnable element)
085            {
086                try
087                {
088                    element.run();
089                } catch (RuntimeException ex)
090                {
091                    logger.error(ServiceMessages.shutdownListenerError(element, ex), ex);
092                }
093            }
094        });
095
096        preListeners.clear();
097        listeners.clear();
098    }
099
100}