// Copyright 2004, 2005 The Apache Software Foundation
//
// Licensed 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.hivemind.impl;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hivemind.ShutdownCoordinator;
import org.apache.hivemind.events.RegistryShutdownListener;
import org.apache.hivemind.util.EventListenerList;
/**
* Manages a list of objects that implement the
* {@link org.apache.hivemind.events.RegistryShutdownListener} interface.
*
* @author Howard Lewis Ship
*/
public final class ShutdownCoordinatorImpl implements ShutdownCoordinator
{
private final Log _log;
private Set alreadyShutdown;
public ShutdownCoordinatorImpl()
{
this(LogFactory.getLog(ShutdownCoordinatorImpl.class));
}
public ShutdownCoordinatorImpl(Log log)
{
_log = log;
}
private EventListenerList _listenerList;
public synchronized void addRegistryShutdownListener(
RegistryShutdownListener s)
{
if (_listenerList == null)
_listenerList = new EventListenerList();
_listenerList.addListener(s);
}
public synchronized void removeRegistryShutdownListener(
RegistryShutdownListener s)
{
if (_listenerList != null)
_listenerList.removeListener(s);
}
public void shutdown()
{
if (_listenerList == null)
return;
Iterator i = _listenerList.getListeners();
_listenerList = null;
while (i.hasNext())
{
RegistryShutdownListener s = (RegistryShutdownListener) i.next();
shutdown(s);
}
_listenerList = null;
}
private void shutdown(RegistryShutdownListener s)
{
if (alreadyShutdown == null)
{
alreadyShutdown = new HashSet();
}
final Long id = new Long(System.identityHashCode(s));
if (!alreadyShutdown.contains(id))
{
try
{
s.registryDidShutdown();
}
catch (RuntimeException ex)
{
_log.error(ImplMessages.shutdownCoordinatorFailure(s, ex), ex);
}
finally
{
alreadyShutdown.add(id);
}
}
}
}