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ActiveMQ example source code file (SocketProxy.java)

This example ActiveMQ source code file (SocketProxy.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - ActiveMQ tags/keywords

acceptor, atomicreference, bridge, countdownlatch, countdownlatch, exception, exception, io, net, network, pump, serversocket, socket, socket, socketproxy, threading, threads, uri, uri, util

The ActiveMQ SocketProxy.java source code

/**
 * 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.activemq.util;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.net.SocketTimeoutException;
import java.net.URI;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class SocketProxy {

    private static final transient Logger LOG = LoggerFactory.getLogger(SocketProxy.class);

    public static final int ACCEPT_TIMEOUT_MILLIS = 100;

    private URI proxyUrl;
    private URI target;

    private Acceptor acceptor;
    private ServerSocket serverSocket;
    
    private CountDownLatch closed = new CountDownLatch(1);

    public List<Bridge> connections = new LinkedList();

    private int listenPort = 0;

    private int receiveBufferSize = -1;

    private boolean pauseAtStart = false;

    private int acceptBacklog = 50;

    public SocketProxy() throws Exception {    
    }
    
    public SocketProxy(URI uri) throws Exception {
        this(0, uri);
    }

    public SocketProxy(int port, URI uri) throws Exception {
        listenPort = port;
        target = uri;
        open();
    }

    public void setReceiveBufferSize(int receiveBufferSize) {
        this.receiveBufferSize = receiveBufferSize;
    }
    
    public void setTarget(URI tcpBrokerUri) {
        target = tcpBrokerUri;
    }

    public void open() throws Exception {
        serverSocket = new ServerSocket();
        serverSocket.setReuseAddress(true);
        if (receiveBufferSize > 0) {
            serverSocket.setReceiveBufferSize(receiveBufferSize);
        }
        if (proxyUrl == null) {
            serverSocket.bind(new InetSocketAddress(listenPort), acceptBacklog);
            proxyUrl = urlFromSocket(target, serverSocket);
        } else {
            serverSocket.bind(new InetSocketAddress(proxyUrl.getPort()));
        }
        acceptor = new Acceptor(serverSocket, target);
        if (pauseAtStart) {
            acceptor.pause();
        }
        new Thread(null, acceptor, "SocketProxy-Acceptor-" + serverSocket.getLocalPort()).start();
        closed = new CountDownLatch(1);
    }

    public URI getUrl() {
        return proxyUrl;
    }

    /*
     * close all proxy connections and acceptor
     */
    public void close() {
        List<Bridge> connections;
        synchronized(this.connections) {
            connections = new ArrayList<Bridge>(this.connections);
        }            
        LOG.info("close, numConnectons=" + connections.size());
        for (Bridge con : connections) {
            closeConnection(con);
        }
        acceptor.close();
        closed.countDown();
    }

    /*
     * close all proxy receive connections, leaving acceptor
     * open
     */
    public void halfClose() {
        List<Bridge> connections;
        synchronized(this.connections) {
            connections = new ArrayList<Bridge>(this.connections);
        }            
        LOG.info("halfClose, numConnectons=" + connections.size());
        for (Bridge con : connections) {
            halfCloseConnection(con);
        }
    }

    public boolean waitUntilClosed(long timeoutSeconds) throws InterruptedException {
        return closed.await(timeoutSeconds, TimeUnit.SECONDS);
    }

    /*
     * called after a close to restart the acceptor on the same port
     */
    public void reopen() {
        LOG.info("reopen");
        try {
            open();
        } catch (Exception e) {
            LOG.debug("exception on reopen url:" + getUrl(), e);
        }
    }

    /*
     * pause accepting new connecitons and data transfer through existing proxy
     * connections. All sockets remain open
     */
    public void pause() {
        synchronized(connections) {
            LOG.info("pause, numConnectons=" + connections.size());
            acceptor.pause();
            for (Bridge con : connections) {
                con.pause();
            }
        }
    }

    /*
     * continue after pause
     */
    public void goOn() {
        synchronized(connections) {
            LOG.info("goOn, numConnectons=" + connections.size());
            for (Bridge con : connections) {
                con.goOn();
            }
        }
        acceptor.goOn();
    }

    private void closeConnection(Bridge c) {
        try {
            c.close();
        } catch (Exception e) {
            LOG.debug("exception on close of: " + c, e);
        }
    }

    private void halfCloseConnection(Bridge c) {
        try {
            c.halfClose();
        } catch (Exception e) {
            LOG.debug("exception on half close of: " + c, e);
        }
    }

    public boolean isPauseAtStart() {
        return pauseAtStart;
    }

    public void setPauseAtStart(boolean pauseAtStart) {
        this.pauseAtStart = pauseAtStart;
    }

    public int getAcceptBacklog() {
        return acceptBacklog;
    }

    public void setAcceptBacklog(int acceptBacklog) {
        this.acceptBacklog = acceptBacklog;
    }

    private URI urlFromSocket(URI uri, ServerSocket serverSocket) throws Exception {
        int listenPort = serverSocket.getLocalPort();

        return new URI(uri.getScheme(), uri.getUserInfo(), uri.getHost(), listenPort, uri.getPath(), uri.getQuery(), uri.getFragment());
    }

    public class Bridge {

        private Socket receiveSocket;
        private Socket sendSocket;
        private Pump requestThread;
        private Pump responseThread;

        public Bridge(Socket socket, URI target) throws Exception {
            receiveSocket = socket;
            sendSocket = new Socket();
            if (receiveBufferSize > 0) {
                sendSocket.setReceiveBufferSize(receiveBufferSize);
            }
            sendSocket.connect(new InetSocketAddress(target.getHost(), target.getPort()));
            linkWithThreads(receiveSocket, sendSocket);
            LOG.info("proxy connection " + sendSocket + ", receiveBufferSize=" + sendSocket.getReceiveBufferSize());
        }

        public void goOn() {
            responseThread.goOn();
            requestThread.goOn();
        }

        public void pause() {
            requestThread.pause();
            responseThread.pause();
        }

        public void close() throws Exception {
            synchronized(connections) {
                connections.remove(this);
            }
            receiveSocket.close();
            sendSocket.close();
        }

        public void halfClose() throws Exception {
            receiveSocket.close();
        }

        private void linkWithThreads(Socket source, Socket dest) {
            requestThread = new Pump(source, dest);
            requestThread.start();
            responseThread = new Pump(dest, source);
            responseThread.start();
        }

        public class Pump extends Thread {

            protected Socket src;
            private Socket destination;
            private AtomicReference<CountDownLatch> pause = new AtomicReference();

            public Pump(Socket source, Socket dest) {
                super("SocketProxy-DataTransfer-" + source.getPort() + ":" + dest.getPort());
                src = source;
                destination = dest;
                pause.set(new CountDownLatch(0));
            }

            public void pause() {
                pause.set(new CountDownLatch(1));
            }

            public void goOn() {
                pause.get().countDown();
            }

            public void run() {
                byte[] buf = new byte[1024];
                try {
                    InputStream in = src.getInputStream();
                    OutputStream out = destination.getOutputStream();
                    while (true) {
                        int len = in.read(buf);
                        if (len == -1) {
                            LOG.debug("read eof from:" + src);
                            break;
                        }
                        pause.get().await();
                        out.write(buf, 0, len);
                    }
                } catch (Exception e) {
                    LOG.debug("read/write failed, reason: " + e.getLocalizedMessage());
                    try {
                        if (!receiveSocket.isClosed()) {
                            // for halfClose, on read/write failure if we close the
                            // remote end will see a close at the same time.
                            close();
                        }
                    } catch (Exception ignore) {
                    }
                }
            }
        }
    }

    public class Acceptor implements Runnable {

        private ServerSocket socket;
        private URI target;
        private AtomicReference<CountDownLatch> pause = new AtomicReference();


        public Acceptor(ServerSocket serverSocket, URI uri) {
            socket = serverSocket;
            target = uri;
            pause.set(new CountDownLatch(0));
            try {
                socket.setSoTimeout(ACCEPT_TIMEOUT_MILLIS);
            } catch (SocketException e) {
                e.printStackTrace();
            }
        }

        public void pause() {
            pause.set(new CountDownLatch(1));
        }
        
        public void goOn() {
            pause.get().countDown();
        }

        public void run() {
            try {
                while(!socket.isClosed()) {
                    pause.get().await();
                    try {
                        Socket source = socket.accept();
                        pause.get().await();
                        if (receiveBufferSize > 0) {
                            source.setReceiveBufferSize(receiveBufferSize);
                        }
                        LOG.info("accepted " + source + ", receiveBufferSize:" + source.getReceiveBufferSize());
                        synchronized(connections) {
                            connections.add(new Bridge(source, target));
                        }
                    } catch (SocketTimeoutException expected) {
                    }
                }
            } catch (Exception e) {
                LOG.debug("acceptor: finished for reason: " + e.getLocalizedMessage());
            }
        }
        
        public void close() {
            try {
                socket.close();
                closed.countDown();
                goOn();
            } catch (IOException ignored) {
            }
        }
    }

}

Other ActiveMQ examples (source code examples)

Here is a short list of links related to this ActiveMQ SocketProxy.java source code file:

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