libjava/java/net/MulticastSocket.java

// MulticastSocket.java

/* Copyright (C) 1999, 2000  Free Software Foundation

   This file is part of libgcj.

This software is copyrighted work licensed under the terms of the
Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
details.  */

package java.net;
import java.io.IOException;

/**
 * @author Warren Levy <warrenl@cygnus.com>
 * @date May 18, 1999.
 */

/**
 * Written using on-line Java Platform 1.2 API Specification, as well
 * as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998).
 * Status:  Believed complete and correct.
 */

public class MulticastSocket extends DatagramSocket
{
  // FIXME: the local addr bound to the multicast socket can be reused;
  // unlike unicast sockets.  It binds to any available network interface.
  // See p.1159 JCL book.

  public MulticastSocket() throws IOException
  {
    super(0, ServerSocket.ANY_IF);
  }

  public MulticastSocket(int port) throws IOException
  {
    super(port, ServerSocket.ANY_IF);
  }

  public InetAddress getInterface() throws SocketException
  {
    // FIXME: Is it possible that an InetAddress wasn't returned from getOption?
    return (InetAddress) impl.getOption(SocketOptions.IP_MULTICAST_IF);
  }

  // Deprecated in JDK1.2
  public byte getTTL() throws IOException
  {
    // Use getTTL here rather than getTimeToLive in case we're using an impl
    // other than the default PlainDatagramSocketImpl and it doesn't have
    // getTimeToLive yet.
    return impl.getTTL();
  }

  // JDK1.2
  public int getTimeToLive() throws IOException
  {
    return impl.getTimeToLive();
  }

  public void setInterface(InetAddress inf) throws SocketException
  {
    impl.setOption(SocketOptions.IP_MULTICAST_IF, inf);
  }

  // Deprecated in JDK1.2
  public void setTTL(byte ttl) throws IOException
  {
    // Use setTTL here rather than setTimeToLive in case we're using an impl
    // other than the default PlainDatagramSocketImpl and it doesn't have
    // setTimeToLive yet.
    impl.setTTL(ttl);
  }

  // JDK1.2
  public void setTimeToLive(int ttl) throws IOException
  {
    if (ttl <= 0 || ttl > 255)
      throw new IllegalArgumentException("Invalid ttl: " + ttl);

    impl.setTimeToLive(ttl);
  }

  public void joinGroup(InetAddress mcastaddr) throws IOException
  {
    if (! mcastaddr.isMulticastAddress())
      throw new IOException("Not a Multicast address");

    SecurityManager s = System.getSecurityManager();
    if (s != null)
      s.checkMulticast(mcastaddr);

    impl.join(mcastaddr);
  }

  public void leaveGroup(InetAddress mcastaddr) throws IOException
  {
    if (! mcastaddr.isMulticastAddress())
      throw new IOException("Not a Multicast address");

    SecurityManager s = System.getSecurityManager();
    if (s != null)
      s.checkMulticast(mcastaddr);

    impl.leave(mcastaddr);
  }

  public synchronized void send(DatagramPacket p, byte ttl) throws IOException
  {
    SecurityManager s = System.getSecurityManager();
    if (s != null)
      {
	InetAddress addr = p.getAddress();
	if (addr.isMulticastAddress())
	  s.checkMulticast(addr, ttl);
	else
	  s.checkConnect(addr.getHostAddress(), p.getPort());
      }

    int oldttl = impl.getTimeToLive();
    impl.setTimeToLive(((int) ttl) & 0xFF);
    impl.send(p);
    impl.setTimeToLive(oldttl);
  }
}