package org.apache.commons.jcs.utils.discovery;
   
   /*
    * 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.
   */
  
  import org.apache.commons.jcs.engine.CacheInfo;
  import org.apache.commons.jcs.utils.discovery.UDPDiscoveryMessage.BroadcastType;
  import org.apache.commons.jcs.utils.serialization.StandardSerializer;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.net.DatagramPacket;
  import java.net.InetAddress;
  import java.net.MulticastSocket;
  import java.util.ArrayList;
  
  /**
   * This is a generic sender for the UDPDiscovery process.
   * <p>
   * @author Aaron Smuts
   */
  public class UDPDiscoverySender
  {
      /** The logger. */
      private static final Log log = LogFactory.getLog( UDPDiscoverySender.class );
  
      /** The socket */
      private MulticastSocket localSocket;
  
      /** The address */
      private InetAddress multicastAddress;
  
      /** The port */
      private final int multicastPort;
  
      /** Used to serialize messages */
      private final StandardSerializer serializer = new StandardSerializer();
  
      /**
       * Constructor for the UDPDiscoverySender object
       * <p>
       * This sender can be used to send multiple messages.
       * <p>
       * When you are done sending, you should destroy the socket sender.
       * <p>
       * @param host
       * @param port
       * @throws IOException
       */
      public UDPDiscoverySender( String host, int port )
          throws IOException
      {
          try
          {
              if ( log.isDebugEnabled() )
              {
                  log.debug( "Constructing socket for sender on port [" + port + "]" );
              }
              localSocket = new MulticastSocket( port );
  
              // Remote address.
              multicastAddress = InetAddress.getByName( host );
          }
          catch ( IOException e )
          {
              log.error( "Could not bind to multicast address [" + host + "]", e );
  
              throw e;
          }
  
          multicastPort = port;
      }
  
      /**
       * Closes the socket connection.
       */
      public void destroy()
      {
          try
          {
              if ( this.localSocket != null && !this.localSocket.isClosed() )
             {
                 this.localSocket.close();
             }
         }
         catch ( Exception e )
         {
             log.error( "Problem destrying sender", e );
         }
     }
 
     /**
      * Just being careful about closing the socket.
      * <p>
      * @throws Throwable
      */
     @Override
     protected void finalize()
         throws Throwable
     {
         super.finalize();
         destroy();
     }
 
     /**
      * Send messages.
      * <p>
      * @param message
      * @throws IOException
      */
     public void send( UDPDiscoveryMessage message )
         throws IOException
     {
         if ( this.localSocket == null )
         {
             throw new IOException( "Socket is null, cannot send message." );
         }
 
         if ( this.localSocket.isClosed() )
         {
             throw new IOException( "Socket is closed, cannot send message." );
         }
 
         if ( log.isDebugEnabled() )
         {
             log.debug( "sending UDPDiscoveryMessage, address [" + multicastAddress + "], port [" + multicastPort
                 + "], message = " + message );
         }
 
         try
         {
             final byte[] bytes = serializer.serialize( message );
 
             // put the byte array in a packet
             final DatagramPacket packet = new DatagramPacket( bytes, bytes.length, multicastAddress, multicastPort );
 
             if ( log.isDebugEnabled() )
             {
                 log.debug( "Sending DatagramPacket. bytes.length [" + bytes.length + "] to " + multicastAddress + ":"
                     + multicastPort );
             }
 
             localSocket.send( packet );
         }
         catch ( IOException e )
         {
             log.error( "Error sending message", e );
             throw e;
         }
     }
 
     /**
      * Ask other to broadcast their info the the multicast address. If a lateral is non receiving it
      * can use this. This is also called on startup so we can get info.
      * <p>
      * @throws IOException
      */
     public void requestBroadcast()
         throws IOException
     {
         if ( log.isDebugEnabled() )
         {
             log.debug( "sending requestBroadcast " );
         }
 
         UDPDiscoveryMessage message = new UDPDiscoveryMessage();
         message.setRequesterId( CacheInfo.listenerId );
         message.setMessageType( BroadcastType.REQUEST );
         send( message );
     }
 
     /**
      * This sends a message broadcasting out that the host and port is available for connections.
      * <p>
      * It uses the vmid as the requesterDI
      * @param host
      * @param port
      * @param cacheNames
      * @throws IOException
      */
     public void passiveBroadcast( String host, int port, ArrayList<String> cacheNames )
         throws IOException
     {
         passiveBroadcast( host, port, cacheNames, CacheInfo.listenerId );
     }
 
     /**
      * This allows you to set the sender id. This is mainly for testing.
      * <p>
      * @param host
      * @param port
      * @param cacheNames names of the cache regions
      * @param listenerId
      * @throws IOException
      */
     protected void passiveBroadcast( String host, int port, ArrayList<String> cacheNames, long listenerId )
         throws IOException
     {
         if ( log.isDebugEnabled() )
         {
             log.debug( "sending passiveBroadcast " );
         }
 
         UDPDiscoveryMessage message = new UDPDiscoveryMessage();
         message.setHost( host );
         message.setPort( port );
         message.setCacheNames( cacheNames );
         message.setRequesterId( listenerId );
         message.setMessageType( BroadcastType.PASSIVE );
         send( message );
     }
 
     /**
      * This sends a message broadcasting our that the host and port is no longer available.
      * <p>
      * It uses the vmid as the requesterID
      * <p>
      * @param host host
      * @param port port
      * @param cacheNames names of the cache regions
      * @throws IOException on error
      */
     public void removeBroadcast( String host, int port, ArrayList<String> cacheNames )
         throws IOException
     {
         removeBroadcast( host, port, cacheNames, CacheInfo.listenerId );
     }
 
     /**
      * This allows you to set the sender id. This is mainly for testing.
      * <p>
      * @param host host
      * @param port port
      * @param cacheNames names of the cache regions
      * @param listenerId listener ID
      * @throws IOException on error
      */
     protected void removeBroadcast( String host, int port, ArrayList<String> cacheNames, long listenerId )
         throws IOException
     {
         if ( log.isDebugEnabled() )
         {
             log.debug( "sending removeBroadcast " );
         }
 
         UDPDiscoveryMessage message = new UDPDiscoveryMessage();
         message.setHost( host );
         message.setPort( port );
         message.setCacheNames( cacheNames );
         message.setRequesterId( listenerId );
         message.setMessageType( BroadcastType.REMOVE );
         send( message );
     }
 }
 
 /**
  * This allows us to get the byte array from an output stream.
  * <p>
  * @author asmuts
  * @created January 15, 2002
  */
 
 class MyByteArrayOutputStream
     extends ByteArrayOutputStream
 {
     /**
      * Gets the bytes attribute of the MyByteArrayOutputStream object
      * @return The bytes value
      */
     public byte[] getBytes()
     {
         return buf;
     }
 }