/*
* JBoss, Home of Professional Open Source
*
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* by the @author tags. See the COPYRIGHT.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.netty.channel.socket.nio;
import java.nio.channels.Selector;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.TimeUnit;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelFactoryExecutorResource;
import org.jboss.netty.channel.ChannelFactoryResource;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelSink;
import org.jboss.netty.channel.socket.ClientSocketChannelFactory;
import org.jboss.netty.channel.socket.SocketChannel;
/**
* A {@link ClientSocketChannelFactory} which creates a client-side NIO-based
* {@link SocketChannel}. It utilizes the non-blocking I/O mode which was
* introduced with NIO to serve many number of concurrent connections
* efficiently.
*
* <h3>How threads work</h3>
* <p>
* There are two types of threads in a {@link NioClientSocketChannelFactory};
* one is boss thread and the other is worker thread.
*
* <h4>Boss thread</h4>
* <p>
* One {@link NioClientSocketChannelFactory} has one boss thread. It makes
* a connection attempt on request. Once a connection attempt succeeds,
* the boss thread passes the connected {@link Channel} to one of the worker
* threads that the {@link NioClientSocketChannelFactory} manages.
*
* <h4>Worker threads</h4>
* <p>
* One {@link NioClientSocketChannelFactory} can have one or more worker
* threads. A worker thread performs non-blocking read and write for one or
* more {@link Channel}s in a non-blocking mode.
*
* <h3>Life cycle of threads and graceful shutdown</h3>
* TODO: Rewrite this section to recommend a user to call ChannelFactoryResource.release().
* <p>
* All threads are acquired from the {@link Executor}s which were specified
* when a {@link NioClientSocketChannelFactory} was created. A boss thread is
* acquired from the {@code bossExecutor}, and worker threads are acquired from
* the {@code workerExecutor}. Therefore, you should make sure the specified
* {@link Executor}s are able to lend the sufficient number of threads.
* It is the best bet to specify {@linkplain Executors#newCachedThreadPool() a cached thread pool}.
* <p>
* Both boss and worker threads are acquired lazily, and then released when
* there's nothing left to process. All the related resources such as
* {@link Selector} are also released when the boss and worker threads are
* released. Therefore, to shut down a service gracefully, you should do the
* following:
*
* <ol>
* <li>close all channels created by the factory,</li>
* <li>call {@link ExecutorService#shutdownNow()} or {@link ExecutorService#shutdown()}
* for all executors which were specified to create the factory, and</li>
* <li>call {@link ExecutorService#awaitTermination(long, TimeUnit)}
* until it returns {@code true}.</li>
* </ol>
*
* Please make sure not to shut down the executor until all channels are
* closed. Otherwise, you will end up with a {@link RejectedExecutionException}
* and the related resources might not be released properly.
*
* @author The Netty Project (netty-dev@lists.jboss.org)
* @author Trustin Lee (tlee@redhat.com)
*
* @version $Rev: 520 $, $Date: 2008-11-26 19:30:21 +0900 (Wed, 26 Nov 2008) $
*
* @apiviz.landmark
*/
public class NioClientSocketChannelFactory implements ClientSocketChannelFactory {
private final ChannelFactoryResource externalResource;
private final ChannelSink sink;
/**
* Creates a new instance. Calling this constructor is same with calling
* {@link #NioClientSocketChannelFactory(Executor, Executor, int)} with
* the number of available processors in the machine. The number of
* available processors is obtained by {@link Runtime#availableProcessors()}.
*
* @param bossExecutor
* the {@link Executor} which will execute the boss thread
* @param workerExecutor
* the {@link Executor} which will execute the I/O worker threads
*/
public NioClientSocketChannelFactory(
Executor bossExecutor, Executor workerExecutor) {
this(bossExecutor, workerExecutor, Runtime.getRuntime().availableProcessors());
}
/**
* Creates a new instance.
*
* @param bossExecutor
* the {@link Executor} which will execute the boss thread
* @param workerExecutor
* the {@link Executor} which will execute the I/O worker threads
* @param workerCount
* the maximum number of I/O worker threads
*/
public NioClientSocketChannelFactory(
Executor bossExecutor, Executor workerExecutor,
int workerCount) {
if (bossExecutor == null) {
throw new NullPointerException("bossExecutor");
}
if (workerExecutor == null) {
throw new NullPointerException("workerExecutor");
}
if (workerCount <= 0) {
throw new IllegalArgumentException(
"workerCount (" + workerCount + ") " +
"must be a positive integer.");
}
externalResource = new ChannelFactoryExecutorResource(bossExecutor, workerExecutor);
sink = new NioClientSocketPipelineSink(bossExecutor, workerExecutor, workerCount);
}
public SocketChannel newChannel(ChannelPipeline pipeline) {
return new NioClientSocketChannel(this, pipeline, sink);
}
public ChannelFactoryResource getExternalResource() {
return externalResource;
}
}