// ========================================================================
   // Copyright (c) Webtide LLC
   // ------------------------------------------------------------------------
   // All rights reserved. This program and the accompanying materials
   // are made available under the terms of the Eclipse Public License v1.0
   // and Apache License v2.0 which accompanies this distribution.
   // The Eclipse Public License is available at 
   // http://www.eclipse.org/legal/epl-v10.html
   // The Apache License v2.0 is available at
  // http://www.opensource.org/licenses/apache2.0.php
  // You may elect to redistribute this code under either of these licenses. 
  // ========================================================================
  
  package org.eclipse.jetty.monitor.jmx;
  
  import java.io.IOException;
  import java.lang.management.ManagementFactory;
  
  import javax.management.MBeanServer;
  import javax.management.MBeanServerConnection;
  import javax.management.remote.JMXConnector;
  import javax.management.remote.JMXConnectorFactory;
  import javax.management.remote.JMXConnectorServer;
  import javax.management.remote.JMXConnectorServerFactory;
  import javax.management.remote.JMXServiceURL;
  
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  
  
  /* ------------------------------------------------------------ */
  /**
   * ServerConnection
   * 
   * Provides ability to create a connection to either an external
   * JMX server, or a loopback connection to the internal one.
   */
  public class ServiceConnection
  {
      private static final Logger LOG = Log.getLogger(ServiceConnection.class);
  
      private String _serviceUrl;
      private MBeanServer _server;
      private JMXConnectorServer _connectorServer;
      private JMXConnector _serverConnector;
      private MBeanServerConnection _serviceConnection;
      
      /* ------------------------------------------------------------ */
      /**
       * Construct a loopback connection to an internal server
       * 
       * @throws IOException
       */
      public ServiceConnection()
          throws IOException
      {
          this(null);
      }
      
      /* ------------------------------------------------------------ */
      /**
       * Construct a connection to specified server
       * 
       * @param url URL of JMX server
       * @throws IOException
       */
      public ServiceConnection(String url)
          throws IOException
      {
          _serviceUrl = url;
      }
      
      /**
       * Retrieve an external URL for the JMX server
       * 
       * @return service URL
       */
      public String getServiceUrl()
      {
      	return _serviceUrl;
      }
      
      /* ------------------------------------------------------------ */
      /**
       * Retrieve a connection to MBean server
       * 
       * @return connection to MBean server
       */
      public MBeanServerConnection getConnection()
      {
          return _serviceConnection;
      }
  
      public void connect()
          throws IOException
      {
          if (_serviceConnection == null)
          {
              if (_serviceUrl == null)
                 openLoopbackConnection();
             else
                 openServerConnection(_serviceUrl);
         }
     }
     /* ------------------------------------------------------------ */
     /**
      * Open a loopback connection to local JMX server
      * 
      * @throws IOException
      */
     private void openLoopbackConnection()
         throws IOException
     {
         _server = ManagementFactory.getPlatformMBeanServer();       
 
         JMXServiceURL serviceUrl = new JMXServiceURL("service:jmx:rmi://");
         _connectorServer = JMXConnectorServerFactory.newJMXConnectorServer(serviceUrl, null, _server);
         _connectorServer.start();
         
         _serviceUrl = _connectorServer.getAddress().toString();
         
         _serverConnector = JMXConnectorFactory.connect(_connectorServer.getAddress());      
         _serviceConnection = _serverConnector.getMBeanServerConnection();
     }
     
     /* ------------------------------------------------------------ */
     /**
      * Open a connection to remote JMX server
      * 
      * @param url
      * @throws IOException
      */
     private void openServerConnection(String url)
         throws IOException
     {
         _serviceUrl = url;
         
         JMXServiceURL serviceUrl = new JMXServiceURL(_serviceUrl);
         _serverConnector = JMXConnectorFactory.connect(serviceUrl);
         _serviceConnection = _serverConnector.getMBeanServerConnection();
     }
     
     /* ------------------------------------------------------------ */
     /**
      * Close the connections
      */
     public void disconnect()
     {
         try
         {
             if (_serverConnector != null)
             {
                 _serverConnector.close();
                 _serviceConnection = null;
             }
             if (_connectorServer != null)
             {
                 _connectorServer.stop();
                 _connectorServer = null;
             }
         }
         catch (Exception ex)
         {
             LOG.debug(ex);
         }
     }
 }