/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you 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.jboss.netty.channel.socket.nio.client;
import java.nio.channels.Selector;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.RejectedExecutionException;
import org.jboss.netty.channel.core.Channel;
import org.jboss.netty.channel.core.ChannelPipeline;
import org.jboss.netty.channel.socket.ClientSocketChannelFactory;
import org.jboss.netty.channel.socket.SocketChannel;
import org.jboss.netty.channel.socket.nio.BossPool;
import org.jboss.netty.channel.socket.nio.NioWorker;
import org.jboss.netty.channel.socket.nio.NioWorkerPool;
import org.jboss.netty.channel.socket.nio.SelectorUtil;
import org.jboss.netty.channel.socket.nio.WorkerPool;
import org.jboss.netty.util.ExternalResourceReleasable;
import org.jboss.netty.util.Timer;
/**
* 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>
* <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 usually using
* {@link ChannelGroup#close()}, and</li>
* <li>call {@link #releaseExternalResources()}.</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.
*
* @apiviz.landmark
*/
public class NioClientSocketChannelFactory implements ClientSocketChannelFactory {
private static final int DEFAULT_BOSS_COUNT = 1;
private final BossPool<NioClientBoss> bossPool;
private final WorkerPool<NioWorker> workerPool;
private final NioClientSocketPipelineSink sink;
private boolean releasePools;
/**
* Creates a new {@link NioClientSocketChannelFactory} which uses {@link Executors#newCachedThreadPool()}
* for the worker and boss executors.
*
* See {@link #NioClientSocketChannelFactory(Executor, Executor)}
*/
public NioClientSocketChannelFactory() {
this(Executors.newCachedThreadPool(), Executors.newCachedThreadPool());
releasePools = true;
}
/**
* Creates a new instance. Calling this constructor is same with calling
* {@link #NioClientSocketChannelFactory(Executor, Executor, int, int)} with
* 1 and (2 * the number of available processors in the machine) for
* <tt>bossCount</tt> and <tt>workerCount</tt> respectively. 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 worker threads
*/
public NioClientSocketChannelFactory(
Executor bossExecutor, Executor workerExecutor) {
this(bossExecutor, workerExecutor, DEFAULT_BOSS_COUNT, SelectorUtil.DEFAULT_IO_THREADS);
}
/**
* Creates a new instance. Calling this constructor is same with calling
* {@link #NioClientSocketChannelFactory(Executor, Executor, int, int)} with
* 1 as <tt>bossCount</tt>.
*
* @param bossExecutor
* the {@link Executor} which will execute the boss thread
* @param workerExecutor
* the {@link Executor} which will execute the worker threads
* @param workerCount
* the maximum number of I/O worker threads
*/
public NioClientSocketChannelFactory(
Executor bossExecutor, Executor workerExecutor, int workerCount) {
this(bossExecutor, workerExecutor, DEFAULT_BOSS_COUNT, workerCount);
}
/**
* Creates a new instance.
*
* @param bossExecutor
* the {@link Executor} which will execute the boss thread
* @param workerExecutor
* the {@link Executor} which will execute the worker threads
* @param bossCount
* the maximum number of boss threads
* @param workerCount
* the maximum number of I/O worker threads
*/
public NioClientSocketChannelFactory(
Executor bossExecutor, Executor workerExecutor,
int bossCount, int workerCount) {
this(bossExecutor, bossCount, new NioWorkerPool(workerExecutor, workerCount));
}
/**
* Creates a new instance.
*
* @param bossExecutor
* the {@link Executor} which will execute the boss thread
* @param bossCount
* the maximum number of boss threads
* @param workerPool
* the {@link WorkerPool} to use to do the IO
*/
public NioClientSocketChannelFactory(
Executor bossExecutor, int bossCount,
WorkerPool<NioWorker> workerPool) {
this(new NioClientBossPool(bossExecutor, bossCount), workerPool);
}
/**
* Creates a new instance.
*
* @param bossExecutor
* the {@link Executor} which will execute the boss thread
* @param bossCount
* the maximum number of boss threads
* @param workerPool
* the {@link WorkerPool} to use to do the IO
* @param timer
* the {@link Timer} to use to handle the connection timeouts
*/
public NioClientSocketChannelFactory(
Executor bossExecutor, int bossCount,
WorkerPool<NioWorker> workerPool, Timer timer) {
this(new NioClientBossPool(bossExecutor, bossCount, timer, null), workerPool);
}
/**
* Creates a new instance.
*
* @param bossPool
* the {@link BossPool} to use to handle the connects
* @param workerPool
* the {@link WorkerPool} to use to do the IO
*/
public NioClientSocketChannelFactory(
BossPool<NioClientBoss> bossPool,
WorkerPool<NioWorker> workerPool) {
if (bossPool == null) {
throw new NullPointerException("bossPool");
}
if (workerPool == null) {
throw new NullPointerException("workerPool");
}
this.bossPool = bossPool;
this.workerPool = workerPool;
sink = new NioClientSocketPipelineSink(bossPool);
}
public SocketChannel newChannel(ChannelPipeline pipeline) {
return new NioClientSocketChannel(this, pipeline, sink, workerPool.nextWorker());
}
public void shutdown() {
bossPool.shutdown();
workerPool.shutdown();
if (releasePools) {
releasePools();
}
}
public void releaseExternalResources() {
bossPool.shutdown();
workerPool.shutdown();
releasePools();
}
private void releasePools() {
if (bossPool instanceof ExternalResourceReleasable) {
((ExternalResourceReleasable) bossPool).releaseExternalResources();
}
if (workerPool instanceof ExternalResourceReleasable) {
((ExternalResourceReleasable) workerPool).releaseExternalResources();
}
}
}
