org.apache.felix.mosgi.jmx.rmiconnector/src/main/java/org/apache/felix/mosgi/jmx/rmiconnector/mx4j/remote/AbstractHeartBeat.java

/*
 * Copyright (C) MX4J.
 * All rights reserved.
 *
 * This software is distributed under the terms of the MX4J License version 1.0.
 * See the terms of the MX4J License in the documentation provided with this software.
 */
/*
 *   Copyright 2005 The Apache Software Foundation
 *
 *   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.apache.felix.mosgi.jmx.rmiconnector.mx4j.remote;

import java.io.IOException;
import java.util.Map;

/**
 *
 * @author <a href="mailto:biorn_steedom@users.sourceforge.net">Simone Bordet</a>
 * @version $Revision: 1.1.1.1 $
 */
public abstract class AbstractHeartBeat implements HeartBeat, Runnable
{
   private final ConnectionNotificationEmitter emitter;
   private long pulsePeriod;
   private int maxRetries;
   private Thread thread;
   private volatile boolean stopped;

   protected AbstractHeartBeat(ConnectionNotificationEmitter emitter, Map environment)
   {
      this.emitter = emitter;
      if (environment != null)
      {
         try
         {
            pulsePeriod = ((Long)environment.get(MX4JRemoteConstants.CONNECTION_HEARTBEAT_PERIOD)).longValue();
         }
         catch (Exception ignored)
         {
         }
         try
         {
            maxRetries = ((Integer)environment.get(MX4JRemoteConstants.CONNECTION_HEARTBEAT_RETRIES)).intValue();
         }
         catch (Exception ignored)
         {
         }
      }
      if (pulsePeriod <= 0) pulsePeriod = 5000;
      if (maxRetries <= 0) maxRetries = 3;
   }

   protected abstract void pulse() throws IOException;

   public void start() throws IOException
   {
      thread = new Thread(this, "Connection HeartBeat");
      thread.setDaemon(true);
      thread.start();
   }

   public void stop() throws IOException
   {
      if (stopped) return;
      stopped = true;
      thread.interrupt();
   }

   public void run()
   {
      int retries = 0;
      while (!stopped && !thread.isInterrupted())
      {
         try
         {
            Thread.sleep(pulsePeriod);

            try
            {
               pulse();
               retries = 0;
            }
            catch (IOException x)
            {
               if (retries++ == maxRetries)
               {
                  // The connection has died
                  sendConnectionNotificationFailed();
                  // And go on
               }
            }
         }
         catch (InterruptedException x)
         {
            Thread.currentThread().interrupt();
            return;
         }
      }
   }

   protected void sendConnectionNotificationFailed()
   {
      emitter.sendConnectionNotificationFailed();
   }
}