reconnect.java

这是一个用java和xml编写的流媒体服务器管理软件

/*
 * ====================================================================
 * The Vovida Software License, Version 1.0
 *
 * Copyright (c) 2000 Vovida Networks, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in
 * the documentation and/or other materials provided with the
 * distribution.
 *
 * 3. The names "VOCAL", "Vovida Open Communication Application Library",
 * and "Vovida Open Communication Application Library (VOCAL)" must
 * not be used to endorse or promote products derived from this
 * software without prior written permission. For written
 * permission, please contact [e-mail].
 *
 * 4. Products derived from this software may not be called "VOCAL", nor
 * may "VOCAL" appear in their name, without prior written
 * permission of Vovida Networks, Inc.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND
 * NON-INFRINGEMENT ARE DISCLAIMED.  IN NO EVENT SHALL VOVIDA
 * NETWORKS, INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT DAMAGES
 * IN EXCESS OF $1,000, NOR FOR ANY INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 * ====================================================================
 *
 * This software consists of voluntary contributions made by Vovida
 * Networks, Inc. and many individuals on behalf of Vovida Networks,
 * Inc.  For more information on Vovida Networks, Inc., please see
 * <http://www.vovida.org/>.
 *
 */

/**
 * Title:        Reconnect.java<p>
 * Description:  see below<p>
 * Copyright:    Copyright (c) 2000 Vovida Networks, Inc.  All rights reserved.<p>
 * Company:      Vovida Networks<p>
 * @author
 * @version 1.0
 */

package vocal.comm;

import java.net.Socket;
import java.net.InetAddress;

import java.io.OutputStreamWriter;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;

/**
 * A simple class which implements the runnable interface and attempts to
 * connect to a given host and port for a number of retries. <p>
 * This is intended to be run in its own thread once a connection to a server
 * has been lost in order to attempt to reconnect. Once the recconnect has
 * succeeded or has failed (exceeded number of retries), the appropriate
 * callback is called.
 */
public class Reconnect implements Runnable
{

  private Transaction respondent;
  private String hostName;
  private int portNumber;

  private static final int MAX_RECONNECT_ATTEMPTS = 30;
  private static final int RECONNECT_DELAY = 3000;
  private static final int SOCKET_TIMEOUT = 2000;

  private int currentAttempt = 0;

  private Socket socket;
  private BufferedReader fromSocket;
  private OutputStreamWriter toSocket;

  private boolean reconnected = false;



  /**
   * @param resp a reference to a class which is to be notified of the result
   * of the connect attempts.
   * @param host a string giving the host name attempt to connect to
   * @param port the port number to attempt to connect to
   */
  public Reconnect(Transaction resp, String host, int port)
  {
    respondent = resp;
    hostName = host;
    portNumber = port;
  }



  public void run()
  {

    while ((currentAttempt < MAX_RECONNECT_ATTEMPTS) && (!reconnected))
    {
      try
      {

        // make sure reconnect attempts should continue;
        if (!respondent.okToReconnect())
        {
          return;
        }

        System.out.println("Reconnect attempt " + currentAttempt + " "
                           + Thread.currentThread().toString());

        socket = new Socket(InetAddress.getByName(hostName), portNumber);

        // disable blocking io by setting a timeout on the
        // socketInputStream.read operation
        socket.setSoTimeout(SOCKET_TIMEOUT);

        fromSocket =
          new BufferedReader(new InputStreamReader(socket.getInputStream()));
        toSocket = new OutputStreamWriter(socket.getOutputStream());

        reconnected = true;

        System.out.println("Reconnect successful. " + Thread.currentThread().toString());
        respondent.reconnected();
      }
      catch (IOException ex)
      {

        try
        {
          Thread.sleep(RECONNECT_DELAY);

          currentAttempt++;
        }
        catch (InterruptedException e)
        {

          // can't throw and exception from run
          System.out.println("ERROR: -------- "
                             + "Reconnect sleep was interrupted.");
        }

      }         // end catch ioException

    }           // end while not reconnected

    if (!reconnected)
    {
      respondent.reconnectFailed();
    }

  }     // end method run


  /**
   * Returns the socket on which the connection was established. <p>
   * Only call this method after the reconnect was successful
   * (the reconnected() method was called on the callback object).
   */
  public Socket getSocket()
  {
    return socket;
  }


  /**
   * Returns the input stream for the socket on which the connection was
   * established. <p>
   * Only call this method after the reconnect was successfull
   * (the reconnected() method was called on the callback object).
   */
  public BufferedReader getInputStream()
  {
    return fromSocket;
  }


  /**
   * Returns the output stream for the socket on which the connection was
   * established. <p>
   * Only call this method after the reconnect was successfull
   * (the reconnected() method was called on the callback object).
   */
  public OutputStreamWriter getOutputStream()
  {
    return toSocket;
  }
}       // end class reconnect