1 /* 2 * Copyright 2009 Red Hat, Inc. 3 * 4 * Red Hat licenses this file to you under the Apache License, version 2.0 5 * (the "License"); you may not use this file except in compliance with the 6 * License. You may obtain a copy of the License at: 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 13 * License for the specific language governing permissions and limitations 14 * under the License. 15 */ 16 package org.jboss.netty.channel.socket.oio; 17 18 import java.util.concurrent.Executor; 19 import java.util.concurrent.RejectedExecutionException; 20 21 import org.jboss.netty.channel.Channel; 22 import org.jboss.netty.channel.ChannelPipeline; 23 import org.jboss.netty.channel.ChannelSink; 24 import org.jboss.netty.channel.group.ChannelGroup; 25 import org.jboss.netty.channel.socket.ServerSocketChannel; 26 import org.jboss.netty.channel.socket.ServerSocketChannelFactory; 27 import org.jboss.netty.util.internal.ExecutorUtil; 28 29 /** 30 * A {@link ServerSocketChannelFactory} which creates a server-side blocking 31 * I/O based {@link ServerSocketChannel}. It utilizes the good old blocking 32 * I/O API which is known to yield better throughput and latency when there 33 * are relatively small number of connections to serve. 34 * 35 * <h3>How threads work</h3> 36 * <p> 37 * There are two types of threads in a {@link OioServerSocketChannelFactory}; 38 * one is boss thread and the other is worker thread. 39 * 40 * <h4>Boss threads</h4> 41 * <p> 42 * Each bound {@link ServerSocketChannel} has its own boss thread. 43 * For example, if you opened two server ports such as 80 and 443, you will 44 * have two boss threads. A boss thread accepts incoming connections until 45 * the port is unbound. Once a connection is accepted successfully, the boss 46 * thread passes the accepted {@link Channel} to one of the worker 47 * threads that the {@link OioServerSocketChannelFactory} manages. 48 * 49 * <h4>Worker threads</h4> 50 * <p> 51 * Each connected {@link Channel} has a dedicated worker thread, just like a 52 * traditional blocking I/O thread model. 53 * 54 * <h3>Life cycle of threads and graceful shutdown</h3> 55 * <p> 56 * All threads are acquired from the {@link Executor}s which were specified 57 * when a {@link OioServerSocketChannelFactory} was created. Boss threads are 58 * acquired from the {@code bossExecutor}, and worker threads are acquired from 59 * the {@code workerExecutor}. Therefore, you should make sure the specified 60 * {@link Executor}s are able to lend the sufficient number of threads. 61 * <p> 62 * Both boss and worker threads are acquired lazily, and then released when 63 * there's nothing left to process. All the related resources are also 64 * released when the boss and worker threads are released. Therefore, to shut 65 * down a service gracefully, you should do the following: 66 * 67 * <ol> 68 * <li>unbind all channels created by the factory, 69 * <li>close all child channels accepted by the unbound channels, 70 * (these two steps so far is usually done using {@link ChannelGroup#close()})</li> 71 * <li>call {@link #releaseExternalResources()}.</li> 72 * </ol> 73 * 74 * Please make sure not to shut down the executor until all channels are 75 * closed. Otherwise, you will end up with a {@link RejectedExecutionException} 76 * and the related resources might not be released properly. 77 * 78 * <h3>Limitation</h3> 79 * <p> 80 * A {@link ServerSocketChannel} created by this factory and its child channels 81 * do not support asynchronous operations. Any I/O requests such as 82 * {@code "write"} will be performed in a blocking manner. 83 * 84 * @author <a href="http://www.jboss.org/netty/">The Netty Project</a> 85 * @author <a href="http://gleamynode.net/">Trustin Lee</a> 86 * 87 * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $ 88 * 89 * @apiviz.landmark 90 */ 91 public class OioServerSocketChannelFactory implements ServerSocketChannelFactory { 92 93 final Executor bossExecutor; 94 private final Executor workerExecutor; 95 private final ChannelSink sink; 96 97 /** 98 * Creates a new instance. 99 * 100 * @param bossExecutor 101 * the {@link Executor} which will execute the boss threads 102 * @param workerExecutor 103 * the {@link Executor} which will execute the I/O worker threads 104 */ 105 public OioServerSocketChannelFactory( 106 Executor bossExecutor, Executor workerExecutor) { 107 if (bossExecutor == null) { 108 throw new NullPointerException("bossExecutor"); 109 } 110 if (workerExecutor == null) { 111 throw new NullPointerException("workerExecutor"); 112 } 113 this.bossExecutor = bossExecutor; 114 this.workerExecutor = workerExecutor; 115 sink = new OioServerSocketPipelineSink(workerExecutor); 116 } 117 118 public ServerSocketChannel newChannel(ChannelPipeline pipeline) { 119 return new OioServerSocketChannel(this, pipeline, sink); 120 } 121 122 public void releaseExternalResources() { 123 ExecutorUtil.terminate(bossExecutor, workerExecutor); 124 } 125 }