org.springframework.boot.devtools.livereload.LiveReloadServer.java Source code

Java tutorial

Introduction

Here is the source code for org.springframework.boot.devtools.livereload.LiveReloadServer.java

Source

/*
 * Copyright 2012-2015 the original author or authors.
 *
 * Licensed 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.springframework.boot.devtools.livereload;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketTimeoutException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.util.Assert;

/**
 * A <a href="http://livereload.com">livereload</a> server.
 *
 * @author Phillip Webb
 * @since 1.3.0
 * @see <a href="http://livereload.com">livereload.com</a>
 */
public class LiveReloadServer {

    /**
     * The default live reload server port.
     */
    public static final int DEFAULT_PORT = 35729;

    private static Log logger = LogFactory.getLog(LiveReloadServer.class);

    private static final int READ_TIMEOUT = (int) TimeUnit.SECONDS.toMillis(4);

    private final int port;

    private final ThreadFactory threadFactory;

    private ServerSocket serverSocket;

    private Thread listenThread;

    private ExecutorService executor = Executors.newCachedThreadPool(new WorkerThreadFactory());

    private List<Connection> connections = new ArrayList<Connection>();

    /**
     * Create a new {@link LiveReloadServer} listening on the default port.
     */
    public LiveReloadServer() {
        this(DEFAULT_PORT);
    }

    /**
     * Create a new {@link LiveReloadServer} listening on the default port with a specific
     * {@link ThreadFactory}.
     * @param threadFactory the thread factory
     */
    public LiveReloadServer(ThreadFactory threadFactory) {
        this(DEFAULT_PORT, threadFactory);
    }

    /**
     * Create a new {@link LiveReloadServer} listening on the specified port.
     * @param port the listen port
     */
    public LiveReloadServer(int port) {
        this(port, new ThreadFactory() {

            @Override
            public Thread newThread(Runnable runnable) {
                return new Thread(runnable);
            }

        });
    }

    /**
     * Create a new {@link LiveReloadServer} listening on the specified port with a
     * specific {@link ThreadFactory}.
     * @param port the listen port
     * @param threadFactory the thread factory
     */
    public LiveReloadServer(int port, ThreadFactory threadFactory) {
        this.port = port;
        this.threadFactory = threadFactory;
    }

    /**
     * Start the livereload server and accept incoming connections.
     * @throws IOException in case of I/O errors
     */
    public synchronized void start() throws IOException {
        Assert.state(!isStarted(), "Server already started");
        logger.debug("Starting live reload server on port " + this.port);
        this.serverSocket = new ServerSocket(this.port);
        this.listenThread = this.threadFactory.newThread(new Runnable() {

            @Override
            public void run() {
                acceptConnections();
            }

        });
        this.listenThread.setDaemon(true);
        this.listenThread.setName("Live Reload Server");
        this.listenThread.start();
    }

    /**
     * Return if the server has been started.
     * @return {@code true} if the server is running
     */
    public synchronized boolean isStarted() {
        return this.listenThread != null;
    }

    /**
     * Return the port that the server is listening on.
     * @return the server port
     */
    public int getPort() {
        return this.port;
    }

    private void acceptConnections() {
        do {
            try {
                Socket socket = this.serverSocket.accept();
                socket.setSoTimeout(READ_TIMEOUT);
                this.executor.execute(new ConnectionHandler(socket));
            } catch (SocketTimeoutException ex) {
                // Ignore
            } catch (Exception ex) {
                if (logger.isDebugEnabled()) {
                    logger.debug("LiveReload server error", ex);
                }
            }
        } while (!this.serverSocket.isClosed());
    }

    /**
     * Gracefully stop the livereload server.
     * @throws IOException in case of I/O errors
     */
    public synchronized void stop() throws IOException {
        if (this.listenThread != null) {
            closeAllConnections();
            try {
                this.executor.shutdown();
                this.executor.awaitTermination(1, TimeUnit.MINUTES);
            } catch (InterruptedException ex) {
                Thread.currentThread().interrupt();
            }
            this.serverSocket.close();
            try {
                this.listenThread.join();
            } catch (InterruptedException ex) {
                Thread.currentThread().interrupt();
            }
            this.listenThread = null;
            this.serverSocket = null;
        }
    }

    private void closeAllConnections() throws IOException {
        synchronized (this.connections) {
            for (Connection connection : this.connections) {
                connection.close();
            }
        }
    }

    /**
     * Trigger livereload of all connected clients.
     */
    public void triggerReload() {
        synchronized (this.connections) {
            for (Connection connection : this.connections) {
                try {
                    connection.triggerReload();
                } catch (Exception ex) {
                    logger.debug("Unable to send reload message", ex);
                }
            }
        }
    }

    private void addConnection(Connection connection) {
        synchronized (this.connections) {
            this.connections.add(connection);
        }
    }

    private void removeConnection(Connection connection) {
        synchronized (this.connections) {
            this.connections.remove(connection);
        }
    }

    /**
     * Factory method used to create the {@link Connection}.
     * @param socket the source socket
     * @param inputStream the socket input stream
     * @param outputStream the socket output stream
     * @return a connection
     * @throws IOException in case of I/O errors
     */
    protected Connection createConnection(Socket socket, InputStream inputStream, OutputStream outputStream)
            throws IOException {
        return new Connection(socket, inputStream, outputStream);
    }

    /**
     * {@link Runnable} to handle a single connection.
     * @see Connection
     */
    private class ConnectionHandler implements Runnable {

        private final Socket socket;

        private final InputStream inputStream;

        ConnectionHandler(Socket socket) throws IOException {
            this.socket = socket;
            this.inputStream = socket.getInputStream();
        }

        @Override
        public void run() {
            try {
                handle();
            } catch (ConnectionClosedException ex) {
                logger.debug("LiveReload connection closed");
            } catch (Exception ex) {
                if (logger.isDebugEnabled()) {
                    logger.debug("LiveReload error", ex);
                }
            }
        }

        private void handle() throws Exception {
            try {
                try {
                    OutputStream outputStream = this.socket.getOutputStream();
                    try {
                        Connection connection = createConnection(this.socket, this.inputStream, outputStream);
                        runConnection(connection);
                    } finally {
                        outputStream.close();
                    }
                } finally {
                    this.inputStream.close();
                }
            } finally {
                this.socket.close();
            }
        }

        private void runConnection(Connection connection) throws IOException, Exception {
            try {
                addConnection(connection);
                connection.run();
            } finally {
                removeConnection(connection);
            }
        }

    }

    /**
     * {@link ThreadFactory} to create the worker threads.
     */
    private static class WorkerThreadFactory implements ThreadFactory {

        private final AtomicInteger threadNumber = new AtomicInteger(1);

        @Override
        public Thread newThread(Runnable r) {
            Thread thread = new Thread(r);
            thread.setDaemon(true);
            thread.setName("Live Reload #" + this.threadNumber.getAndIncrement());
            return thread;
        }

    }

}