    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.commons.internal.services.ServiceMessages;
    018import org.apache.tapestry5.func.F;
    019import org.apache.tapestry5.func.Worker;
    020import org.apache.tapestry5.ioc.internal.util.OneShotLock;
    021import org.apache.tapestry5.ioc.services.RegistryShutdownHub;
    022import org.apache.tapestry5.ioc.services.RegistryShutdownListener;
    023import org.slf4j.Logger;
    024
    025import static org.apache.tapestry5.commons.util.CollectionFactory.newThreadSafeList;
    026
    027import java.util.List;
    028
    029public class RegistryShutdownHubImpl implements RegistryShutdownHub
    030{
    031    private final OneShotLock lock = new OneShotLock();
    032
    033    private final Logger logger;
    034
    035    private final List<Runnable> listeners = newThreadSafeList();
    036
    037    private final List<Runnable> preListeners = newThreadSafeList();
    038
    039    public RegistryShutdownHubImpl(Logger logger)
    040    {
    041        this.logger = logger;
    042    }
    043
    044    @Override
    045    public void addRegistryShutdownListener(final RegistryShutdownListener listener)
    046    {
    047        assert listener != null;
    048
    049        addRegistryShutdownListener(new Runnable()
    050        {
    051            @Override
    052            public void run()
    053            {
    054                listener.registryDidShutdown();
    055            }
    056        });
    057    }
    058
    059    @Override
    060    public void addRegistryShutdownListener(Runnable listener)
    061    {
    062        assert listener != null;
    063
    064        lock.check();
    065
    066        listeners.add(listener);
    067    }
    068
    069    @Override
    070    public void addRegistryWillShutdownListener(Runnable listener)
    071    {
    072        assert listener != null;
    073
    074        lock.check();
    075
    076        preListeners.add(listener);
    077    }
    078
    079    /**
    080     * Fires the {@link RegistryShutdownListener#registryDidShutdown()} method on each listener. At the end, all the
    081     * listeners are discarded.
    082     */
    083    public void fireRegistryDidShutdown()
    084    {
    085        lock.lock();
    086
    087        F.flow(preListeners).concat(listeners).each(new Worker<Runnable>()
    088        {
    089            @Override
    090            public void work(Runnable element)
    091            {
    092                try
    093                {
    094                    element.run();
    095                } catch (RuntimeException ex)
    096                {
    097                    logger.error(ServiceMessages.shutdownListenerError(element, ex), ex);
    098                }
    099            }
    100        });
    101
    102        preListeners.clear();
    103        listeners.clear();
    104    }
    105
    106}