socketacceptor.java

apache 的一个socket框架

/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF 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.apache.mina.transport.socket.nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.atomic.AtomicInteger;

import org.apache.mina.common.ExceptionMonitor;
import org.apache.mina.common.IoAcceptor;
import org.apache.mina.common.IoHandler;
import org.apache.mina.common.IoServiceConfig;
import org.apache.mina.common.support.BaseIoAcceptor;
import org.apache.mina.util.NamePreservingRunnable;
import org.apache.mina.util.NewThreadExecutor;

/**
 * {@link IoAcceptor} for socket transport (TCP/IP).
 *
 * @author The Apache Directory Project ([e-mail])
 * @version $Rev: 389042 $, $Date: 2006-03-27 07:49:41Z $
 */
public class SocketAcceptor extends BaseIoAcceptor {
    private static final AtomicInteger nextId = new AtomicInteger();

    private final Executor executor;

    private final Object lock = new Object();

    private final int id = nextId.getAndIncrement();

    private final String threadName = "SocketAcceptor-" + id;

    private SocketAcceptorConfig defaultConfig = new SocketAcceptorConfig();

    private final Map<SocketAddress, ServerSocketChannel> channels = new ConcurrentHashMap<SocketAddress, ServerSocketChannel>();

    private final Queue<RegistrationRequest> registerQueue = new ConcurrentLinkedQueue<RegistrationRequest>();

    private final Queue<CancellationRequest> cancelQueue = new ConcurrentLinkedQueue<CancellationRequest>();

    private final SocketIoProcessor[] ioProcessors;

    private final int processorCount;

    private Selector selector;

    private Worker worker;

    private int processorDistributor = 0;

    /**
     * Create an acceptor with a single processing thread using a NewThreadExecutor
     */
    public SocketAcceptor() {
        this(1, new NewThreadExecutor());
    }

    /**
     * Create an acceptor with the desired number of processing threads
     *
     * @param processorCount Number of processing threads
     * @param executor       Executor to use for launching threads
     */
    public SocketAcceptor(int processorCount, Executor executor) {
        if (processorCount < 1) {
            throw new IllegalArgumentException(
                    "Must have at least one processor");
        }

        // The default reuseAddress of an accepted socket should be 'true'.
        defaultConfig.getSessionConfig().setReuseAddress(true);

        this.executor = executor;
        this.processorCount = processorCount;
        ioProcessors = new SocketIoProcessor[processorCount];

        for (int i = 0; i < processorCount; i++) {
            ioProcessors[i] = new SocketIoProcessor(
                    "SocketAcceptorIoProcessor-" + id + "." + i, executor);
        }
    }

    /**
     * Binds to the specified <code>address</code> and handles incoming connections with the specified
     * <code>handler</code>.  Backlog value is configured to the value of <code>backlog</code> property.
     *
     * @throws IOException if failed to bind
     */
    public void bind(SocketAddress address, IoHandler handler,
            IoServiceConfig config) throws IOException {
        if (handler == null) {
            throw new NullPointerException("handler");
        }

        if (address != null && !(address instanceof InetSocketAddress)) {
            throw new IllegalArgumentException("Unexpected address type: "
                    + address.getClass());
        }

        if (config == null) {
            config = getDefaultConfig();
        }

        RegistrationRequest request = new RegistrationRequest(address, handler,
                config);

        registerQueue.add(request);

        startupWorker();

        selector.wakeup();

        try {
            request.done.await();
        } catch (InterruptedException e) {
            ExceptionMonitor.getInstance().exceptionCaught(e);
        }

        if (request.exception != null) {
            throw request.exception;
        }
    }

    private synchronized void startupWorker() throws IOException {
        synchronized (lock) {
            if (worker == null) {
                selector = Selector.open();
                worker = new Worker();

                executor.execute(new NamePreservingRunnable(worker));
            }
        }
    }

    public void unbind(SocketAddress address) {
        if (address == null) {
            throw new NullPointerException("address");
        }

        CancellationRequest request = new CancellationRequest(address);

        try {
            startupWorker();
        } catch (IOException e) {
            // IOException is thrown only when Worker thread is not
            // running and failed to open a selector.  We simply throw
            // IllegalArgumentException here because we can simply
            // conclude that nothing is bound to the selector.
            throw new IllegalArgumentException("Address not bound: " + address);
        }

        cancelQueue.add(request);

        selector.wakeup();

        try {
            request.done.await();
        } catch (InterruptedException e) {
            ExceptionMonitor.getInstance().exceptionCaught(e);
        }

        if (request.exception != null) {
            request.exception.fillInStackTrace();

            throw request.exception;
        }
    }

    public void unbindAll() {
        List<SocketAddress> addresses = new ArrayList<SocketAddress>(channels
                .keySet());

        for (SocketAddress address : addresses) {
            unbind(address);
        }
    }

    private class Worker implements Runnable {
        public void run() {
            Thread.currentThread().setName(SocketAcceptor.this.threadName);

            for (;;) {
                try {
                    int nKeys = selector.select();

                    registerNew();

                    if (nKeys > 0) {
                        processSessions(selector.selectedKeys());
                    }

                    cancelKeys();

                    if (selector.keys().isEmpty()) {
                        synchronized (lock) {
                            if (selector.keys().isEmpty()
                                    && registerQueue.isEmpty()
                                    && cancelQueue.isEmpty()) {
                                worker = null;