Jetty example source code file (Monitor.java)

This example Jetty source code file (Monitor.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 - Jetty tags/keywords

io, linenumberreader, linenumberreader, monitor, monitor, net, network, ok\r\n, serversocket, socket, socket, stopmonitor, string, string, thread

The Jetty Monitor.java source code

// ========================================================================
// Copyright 2003-2005 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// 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.mortbay.start;
import java.io.InputStreamReader;
import java.io.LineNumberReader;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

/*-------------------------------------------*/
/** Monitor thread.
 * This thread listens on the port specified by the STOP.PORT system parameter
 * (defaults to -1 for not listening) for request authenticated with the key given by the STOP.KEY
 * system parameter (defaults to "mortbay") for admin requests. 
 * <p>
 * If the stop port is set to zero, then a random port is assigned and the port number
 * is printed to stdout.
 * <p>
 * Commands "stop" and * "status" are currently supported.
 *
 */
public class Monitor extends Thread
{
    private int _port = Integer.getInteger("STOP.PORT", -1).intValue();
    private String _key = System.getProperty("STOP.KEY", null);

    ServerSocket _socket;
    
    Monitor()
    {
        try
        {
            if(_port<0)
                return;
            setDaemon(true);
	    setName("StopMonitor");
            _socket=new ServerSocket(_port,1,InetAddress.getByName("127.0.0.1"));
            if (_port==0)
            {
                _port=_socket.getLocalPort();
                System.out.println(_port);
            }
            
            if (_key==null)
            {
                _key=Long.toString((long)(Long.MAX_VALUE*Math.random()+this.hashCode()+System.currentTimeMillis()),36);
                System.out.println("-DSTOP.KEY="+_key);
            }
        }
        catch(Exception e)
        {
            if (Main._debug)
                e.printStackTrace();
            else
                System.err.println(e.toString());
        }
        if (_socket!=null)
            this.start();
        else
            System.err.println("WARN: Not listening on monitor port: "+_port);
    }
    
    public void run()
    {
        while (true)
        {
            Socket socket=null;
            try{
                socket=_socket.accept();
                
                LineNumberReader lin=
                    new LineNumberReader(new InputStreamReader(socket.getInputStream()));
                String key=lin.readLine();
                if (!_key.equals(key))
                    continue;
                
                String cmd=lin.readLine();
                if (Main._debug) System.err.println("command="+cmd);
                if ("stop".equals(cmd))
                {
                    try {socket.close();}catch(Exception e){e.printStackTrace();}
                    try {_socket.close();}catch(Exception e){e.printStackTrace();}
                    System.exit(0);
                }
                else if ("status".equals(cmd))
                {
                    socket.getOutputStream().write("OK\r\n".getBytes());
                    socket.getOutputStream().flush();
                }
            }
            catch(Exception e)
            {
                if (Main._debug)
                    e.printStackTrace();
                else
                    System.err.println(e.toString());
            }
            finally
            {
                if (socket!=null)
                {
                    try{socket.close();}catch(Exception e){}
                }
                socket=null;
            }
        }
    }

    /** Start a Monitor.
     * This static method starts a monitor that listens for admin requests.
     */
    public static void monitor()
    {
        new Monitor();
    }
 
}