src/main/java/org/apache/log4j/chainsaw/LoggingReceiver.java

/*
 * 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.log4j.chainsaw;

import java.io.EOFException;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import org.apache.log4j.Logger;
import org.apache.log4j.spi.LoggingEvent;

/**
 * A daemon thread the processes connections from a
 * <code>org.apache.log4j.net.SocketAppender.html</code>.
 *
 * @author <a href="mailto:oliver@puppycrawl.com">Oliver Burn</a>
 */
class LoggingReceiver extends Thread {
    /** used to log messages **/
    private static final Logger LOG = Logger.getLogger(LoggingReceiver.class);

    /**
     * Helper that actually processes a client connection. It receives events
     * and adds them to the supplied model.
     *
     * @author <a href="mailto:oliver@puppycrawl.com">Oliver Burn</a>
     */
    private class Slurper implements Runnable {
        /** socket connection to read events from **/
        private final Socket mClient;

        /**
         * Creates a new <code>Slurper</code> instance.
         *
         * @param aClient socket to receive events from
         */
        Slurper(Socket aClient) {
            mClient = aClient;
        }

        /** loops getting the events **/
        public void run() {
            LOG.debug("Starting to get data");
            try {
                final ObjectInputStream ois =
                    new ObjectInputStream(mClient.getInputStream());
                while (true) {
                    final LoggingEvent event = (LoggingEvent) ois.readObject();
                    mModel.addEvent(new EventDetails(event));
                }
            } catch (EOFException e) {
                LOG.info("Reached EOF, closing connection");
            } catch (SocketException e) {
                LOG.info("Caught SocketException, closing connection");
            } catch (IOException e) {
                LOG.warn("Got IOException, closing connection", e);
            } catch (ClassNotFoundException e) {
                LOG.warn("Got ClassNotFoundException, closing connection", e);
            }

            try {
                mClient.close();
            } catch (IOException e) {
                LOG.warn("Error closing connection", e);
            }
        }
    }

    /** where to put the events **/
    private MyTableModel mModel;

    /** server for listening for connections **/
    private ServerSocket mSvrSock;
    
    /**
     * Creates a new <code>LoggingReceiver</code> instance.
     *
     * @param aModel model to place put received into
     * @param aPort port to listen on
     * @throws IOException if an error occurs
     */
    LoggingReceiver(MyTableModel aModel, int aPort) throws IOException {
        setDaemon(true);
        mModel = aModel;
        mSvrSock = new ServerSocket(aPort);
    }

    /** Listens for client connections **/
    public void run() {
        LOG.info("Thread started");
        try {
            while (true) {
                LOG.debug("Waiting for a connection");
                final Socket client = mSvrSock.accept();
                LOG.debug("Got a connection from " +
                          client.getInetAddress().getHostName());
                final Thread t = new Thread(new Slurper(client));
                t.setDaemon(true);
                t.start();
            }
        } catch (IOException e) {
            LOG.error("Error in accepting connections, stopping.", e);
        }
    }
}