datagramacceptordelegate.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.support;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.nio.channels.DatagramChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
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.Executor;
import java.util.concurrent.atomic.AtomicInteger;

import org.apache.mina.common.ByteBuffer;
import org.apache.mina.common.ExceptionMonitor;
import org.apache.mina.common.IoAcceptor;
import org.apache.mina.common.IoFilter.WriteRequest;
import org.apache.mina.common.IoHandler;
import org.apache.mina.common.IoServiceConfig;
import org.apache.mina.common.IoSession;
import org.apache.mina.common.IoSessionRecycler;
import org.apache.mina.common.RuntimeIOException;
import org.apache.mina.common.support.BaseIoAcceptor;
import org.apache.mina.common.support.IoServiceListenerSupport;
import org.apache.mina.transport.socket.nio.DatagramAcceptorConfig;
import org.apache.mina.transport.socket.nio.DatagramServiceConfig;
import org.apache.mina.transport.socket.nio.DatagramSessionConfig;
import org.apache.mina.util.NamePreservingRunnable;

/**
 * {@link IoAcceptor} for datagram transport (UDP/IP).
 *
 * @author The Apache Directory Project ([e-mail])
 * @version $Rev: 555855 $, $Date: 2007-07-13 12:19:00 +0900 (금, 13  7월 2007) $
 */
public class DatagramAcceptorDelegate extends BaseIoAcceptor implements
        IoAcceptor, DatagramService {
    private static final AtomicInteger nextId = new AtomicInteger();

    private final Object lock = new Object();

    private final IoAcceptor wrapper;

    private final Executor executor;

    private final int id = nextId.getAndIncrement();

    private Selector selector;

    private DatagramAcceptorConfig defaultConfig = new DatagramAcceptorConfig();

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

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

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

    private final Queue<DatagramSessionImpl> flushingSessions = new ConcurrentLinkedQueue<DatagramSessionImpl>();

    private Worker worker;

    /**
     * Creates a new instance.
     */
    public DatagramAcceptorDelegate(IoAcceptor wrapper, Executor executor) {
        this.wrapper = wrapper;
        this.executor = executor;

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

    public void bind(SocketAddress address, IoHandler handler,
            IoServiceConfig config) throws IOException {
        if (handler == null)
            throw new NullPointerException("handler");
        if (config == null) {
            config = getDefaultConfig();
        }

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

        RegistrationRequest request = new RegistrationRequest(address, handler,
                config);
        registerQueue.add(request);
        startupWorker();

        selector.wakeup();

        synchronized (request) {
            while (!request.done) {
                try {
                    request.wait();
                } catch (InterruptedException e) {
                    throw new RuntimeIOException(e);
                }
            }
        }

        if (request.exception != null) {
            throw (IOException) new IOException("Failed to bind")
                    .initCause(request.exception);
        }
    }

    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();

        synchronized (request) {
            while (!request.done) {
                try {
                    request.wait();
                } catch (InterruptedException e) {
                    throw new RuntimeIOException(e);
                }
            }
        }

        if (request.exception != null) {
            throw new RuntimeException("Failed to unbind", request.exception);
        }
    }

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

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

    @Override
    public IoSession newSession(SocketAddress remoteAddress,
            SocketAddress localAddress) {
        if (remoteAddress == null) {
            throw new NullPointerException("remoteAddress");
        }
        if (localAddress == null) {
            throw new NullPointerException("localAddress");
        }

        Selector selector = this.selector;
        DatagramChannel ch = channels.get(localAddress);
        if (selector == null || ch == null) {
            throw new IllegalArgumentException("Unknown localAddress: "
                    + localAddress);
        }

        SelectionKey key = ch.keyFor(selector);
        if (key == null) {
            throw new IllegalArgumentException("Unknown localAddress: "
                    + localAddress);
        }

        RegistrationRequest req = (RegistrationRequest) key.attachment();
        IoSession session;
        IoSessionRecycler sessionRecycler = getSessionRecycler(req);
        synchronized (sessionRecycler) {
            session = sessionRecycler.recycle(localAddress, remoteAddress);
            if (session != null) {
                return session;
            }

            // If a new session needs to be created.
            // Note that the local address is the service address in the
            // acceptor side, and I didn't call getLocalSocketAddress().
            // This avoids strange cases where getLocalSocketAddress() on the
            // underlying socket would return an IPv6 address while the
            // specified service address is an IPv4 address.
            DatagramSessionImpl datagramSession = new DatagramSessionImpl(
                    wrapper, this, req.config, ch, req.handler, req.address,
                    req.address);
            datagramSession.setRemoteAddress(remoteAddress);
            datagramSession.setSelectionKey(key);

            getSessionRecycler(req).put(datagramSession);
            session = datagramSession;
        }

        try {
            buildFilterChain(req, session);
            getListeners().fireSessionCreated(session);
        } catch (Throwable t) {
            ExceptionMonitor.getInstance().exceptionCaught(t);
        }

        return session;
    }

    private IoSessionRecycler getSessionRecycler(RegistrationRequest req) {
        IoSessionRecycler sessionRecycler;
        if (req.config instanceof DatagramServiceConfig) {
            sessionRecycler = ((DatagramServiceConfig) req.config)
                    .getSessionRecycler();
        } else {
            sessionRecycler = defaultConfig.getSessionRecycler();
        }
        return sessionRecycler;
    }

    @Override
    public IoServiceListenerSupport getListeners() {
        return super.getListeners();
    }

    private void buildFilterChain(RegistrationRequest req, IoSession session)
            throws Exception {
        this.getFilterChainBuilder().buildFilterChain(session.getFilterChain());
        req.config.getFilterChainBuilder().buildFilterChain(
                session.getFilterChain());
        req.config.getThreadModel().buildFilterChain(session.getFilterChain());
    }

    public DatagramAcceptorConfig getDefaultConfig() {
        return defaultConfig;
    }

    /**
     * Sets the config this acceptor will use by default.
     *
     * @param defaultConfig the default config.
     * @throws NullPointerException if the specified value is <code>null</code>.
     */
    public void setDefaultConfig(DatagramAcceptorConfig defaultConfig) {
        if (defaultConfig == null) {
            throw new NullPointerException("defaultConfig");
        }
        this.defaultConfig = defaultConfig;
    }

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

    public void flushSession(DatagramSessionImpl session) {
        scheduleFlush(session);
        Selector selector = this.selector;
        if (selector != null) {
            selector.wakeup();
        }
    }

    public void closeSession(DatagramSessionImpl session) {
    }

    private void scheduleFlush(DatagramSessionImpl session) {
        flushingSessions.add(session);
    }

    private class Worker implements Runnable {
        public void run() {
            Thread.currentThread().setName("DatagramAcceptor-" + id);

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

                    registerNew();