org.jboss.netty.channel.socket.nio.NioDatagramChannelFactory Maven / Gradle / Ivy
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/*
* 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;
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.ChannelPipeline;
import org.jboss.netty.channel.group.ChannelGroup;
import org.jboss.netty.channel.socket.DatagramChannel;
import org.jboss.netty.channel.socket.DatagramChannelFactory;
import org.jboss.netty.channel.socket.InternetProtocolFamily;
import org.jboss.netty.channel.socket.Worker;
import org.jboss.netty.channel.socket.oio.OioDatagramChannelFactory;
import org.jboss.netty.util.ExternalResourceReleasable;
/**
* A {@link DatagramChannelFactory} that creates a NIO-based connectionless
* {@link DatagramChannel}. It utilizes the non-blocking I/O mode which
* was introduced with NIO to serve many number of concurrent connections
* efficiently.
*
* How threads work
*
* There is only one thread type in a {@link NioDatagramChannelFactory};
* worker threads.
*
*
Worker threads
*
* One {@link NioDatagramChannelFactory} can have one or more worker
* threads. A worker thread performs non-blocking read and write for one or
* more {@link DatagramChannel}s in a non-blocking mode.
*
*
Life cycle of threads and graceful shutdown
*
* All worker threads are acquired from the {@link Executor} which was specified
* when a {@link NioDatagramChannelFactory} was created. Therefore, you should
* make sure the specified {@link Executor} is able to lend the sufficient
* number of threads. It is the best bet to specify
* {@linkplain Executors#newCachedThreadPool() a cached thread pool}.
*
* All 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 worker threads are released. Therefore, to shut
* down a service gracefully, you should do the following:
*
*
* - close all channels created by the factory usually using
* {@link ChannelGroup#close()}, and
* - call {@link #releaseExternalResources()}.
*
*
* 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.
*
* Limitation
*
* Multicast is not supported. Please use {@link OioDatagramChannelFactory}
* instead.
*
* @apiviz.landmark
*/
public class NioDatagramChannelFactory implements DatagramChannelFactory {
private final NioDatagramPipelineSink sink;
private final WorkerPool workerPool;
private final InternetProtocolFamily family;
private boolean releasePool;
/**
* Create a new {@link NioDatagramChannelFactory} with a {@link Executors#newCachedThreadPool()}
* and without preferred {@link InternetProtocolFamily}. Please note that the {@link InternetProtocolFamily}
* of the channel will be platform (and possibly configuration) dependent and therefore
* unspecified. Use {@link #NioDatagramChannelFactory(InternetProtocolFamily)} if unsure.
*
* See {@link #NioDatagramChannelFactory(Executor)}
*/
public NioDatagramChannelFactory() {
this((InternetProtocolFamily) null);
}
/**
* Create a new {@link NioDatagramChannelFactory} with a {@link Executors#newCachedThreadPool()}.
*
* See {@link #NioDatagramChannelFactory(Executor)}
*/
public NioDatagramChannelFactory(InternetProtocolFamily family) {
workerPool = new NioDatagramWorkerPool(Executors.newCachedThreadPool(), SelectorUtil.DEFAULT_IO_THREADS);
this.family = family;
sink = new NioDatagramPipelineSink(workerPool);
releasePool = true;
}
/**
* Creates a new instance. Calling this constructor is same with calling
* {@link #NioDatagramChannelFactory(Executor, int)} with 2 * the number of
* available processors in the machine. The number of available processors
* is obtained by {@link Runtime#availableProcessors()}.
*
* Please note that the {@link InternetProtocolFamily} of the channel will be platform (and possibly
* configuration) dependent and therefore unspecified.
* Use {@link #NioDatagramChannelFactory(Executor, InternetProtocolFamily)} if unsure.
*
* @param workerExecutor
* the {@link Executor} which will execute the I/O worker threads
*/
public NioDatagramChannelFactory(final Executor workerExecutor) {
this(workerExecutor, SelectorUtil.DEFAULT_IO_THREADS);
}
/**
* Creates a new instance.
*
* Please note that the {@link InternetProtocolFamily} of the channel will be platform (and possibly
* configuration) dependent and therefore unspecified.
* Use {@link #NioDatagramChannelFactory(Executor, int, InternetProtocolFamily)} if unsure.
*
* @param workerExecutor
* the {@link Executor} which will execute the I/O worker threads
* @param workerCount
* the maximum number of I/O worker threads
*/
public NioDatagramChannelFactory(final Executor workerExecutor, final int workerCount) {
this(new NioDatagramWorkerPool(workerExecutor, workerCount));
}
/**
* Creates a new instance.
*
* Please note that the {@link InternetProtocolFamily} of the channel will be platform (and possibly
* configuration) dependent and therefore unspecified.
* Use {@link #NioDatagramChannelFactory(WorkerPool, InternetProtocolFamily)} if unsure.
*
* @param workerPool
* the {@link WorkerPool} which will be used to obtain the {@link NioDatagramWorker} that execute
* the I/O worker threads
*/
public NioDatagramChannelFactory(WorkerPool workerPool) {
this(workerPool, null);
}
/**
* Creates a new instance. Calling this constructor is same with calling
* {@link #NioDatagramChannelFactory(Executor, int)} with 2 * the number of
* available processors in the machine. The number of available processors
* is obtained by {@link Runtime#availableProcessors()}.
*
* @param workerExecutor
* the {@link Executor} which will execute the I/O worker threads
* @param family
* the {@link InternetProtocolFamily} to use. This should be used for UDP multicast.
* Be aware that this option is only considered when running on java7+
*/
public NioDatagramChannelFactory(final Executor workerExecutor, InternetProtocolFamily family) {
this(workerExecutor, SelectorUtil.DEFAULT_IO_THREADS, family);
}
/**
* Creates a new instance.
*
* @param workerExecutor
* the {@link Executor} which will execute the I/O worker threads
* @param workerCount
* the maximum number of I/O worker threads
* @param family
* the {@link InternetProtocolFamily} to use. This should be used for UDP multicast.
* Be aware that this option is only considered when running on java7+
*/
public NioDatagramChannelFactory(final Executor workerExecutor,
final int workerCount, InternetProtocolFamily family) {
this(new NioDatagramWorkerPool(workerExecutor, workerCount), family);
}
/**
* Creates a new instance.
*
* @param workerPool
* the {@link WorkerPool} which will be used to obtain the {@link Worker} that execute
* the I/O worker threads
* @param family
* the {@link InternetProtocolFamily} to use. This should be used for UDP multicast.
* Be aware that this option is only considered when running on java7+
*/
public NioDatagramChannelFactory(WorkerPool workerPool, InternetProtocolFamily family) {
this.workerPool = workerPool;
this.family = family;
sink = new NioDatagramPipelineSink(workerPool);
}
public DatagramChannel newChannel(final ChannelPipeline pipeline) {
return new NioDatagramChannel(this, pipeline, sink, sink.nextWorker(), family);
}
public void shutdown() {
workerPool.shutdown();
if (releasePool) {
releasePool();
}
}
public void releaseExternalResources() {
shutdown();
releasePool();
}
private void releasePool() {
if (workerPool instanceof ExternalResourceReleasable) {
((ExternalResourceReleasable) workerPool).releaseExternalResources();
}
}
}