/*
* Copyright (c) 2010-2011 Sonatype, Inc. All rights reserved.
*
* This program is licensed to you under the Apache License Version 2.0,
* and you may not use this file except in compliance with the Apache License Version 2.0.
* You may obtain a copy of the Apache License Version 2.0 at http://www.apache.org/licenses/LICENSE-2.0.
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the Apache License Version 2.0 is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the Apache License Version 2.0 for the specific language governing permissions and limitations there under.
*/
/*
* Copyright 2010 Bruno de Carvalho
*
* 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 com.ning.http.util;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelFuture;
import org.jboss.netty.channel.group.ChannelGroup;
import org.jboss.netty.channel.group.ChannelGroupFuture;
import org.jboss.netty.channel.group.DefaultChannelGroup;
import org.jboss.netty.channel.group.DefaultChannelGroupFuture;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.ArrayList;
import java.util.Collection;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.locks.ReentrantReadWriteLock;
/**
* Extension of {@link DefaultChannelGroup} that's used mainly as a cleanup container, where {@link #close()} is only
* supposed to be called once.
*
* @author <a href="http://bruno.biasedbit.com/">Bruno de Carvalho</a>
*/
public class CleanupChannelGroup extends DefaultChannelGroup {
private final static Logger logger = LoggerFactory.getLogger(CleanupChannelGroup.class);
// internal vars --------------------------------------------------------------------------------------------------
private final AtomicBoolean closed;
private final ReentrantReadWriteLock lock;
// constructors ---------------------------------------------------------------------------------------------------
public CleanupChannelGroup() {
this.closed = new AtomicBoolean(false);
this.lock = new ReentrantReadWriteLock();
}
public CleanupChannelGroup(String name) {
super(name);
this.closed = new AtomicBoolean(false);
this.lock = new ReentrantReadWriteLock();
}
// DefaultChannelGroup --------------------------------------------------------------------------------------------
@Override
public ChannelGroupFuture close() {
this.lock.writeLock().lock();
try {
if (!this.closed.getAndSet(true)) {
// First time close() is called.
return super.close();
} else {
Collection<ChannelFuture> futures = new ArrayList<ChannelFuture>();
logger.debug("CleanupChannelGroup Already closed");
return new DefaultChannelGroupFuture(ChannelGroup.class.cast(this), futures);
}
} finally {
this.lock.writeLock().unlock();
}
}
@Override
public boolean add(Channel channel) {
// Synchronization must occur to avoid add() and close() overlap (thus potentially leaving one channel open).
// This could also be done by synchronizing the method itself but using a read lock here (rather than a
// synchronized() block) allows multiple concurrent calls to add().
this.lock.readLock().lock();
try {
if (this.closed.get()) {
// Immediately close channel, as close() was already called.
channel.close();
return false;
}
return super.add(channel);
} finally {
this.lock.readLock().unlock();
}
}
}