mirror of git://gcc.gnu.org/git/gcc.git
243 lines
7.0 KiB
Java
243 lines
7.0 KiB
Java
/* MulticastSocket.java -- Class for using multicast sockets
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Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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As a special exception, if you link this library with other files to
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produce an executable, this library does not by itself cause the
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resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why the
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executable file might be covered by the GNU General Public License. */
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package java.net;
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import java.io.IOException;
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/*
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* Written using on-line Java Platform 1.2 API Specification, as well
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* as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998).
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* Status: Believed complete and correct.
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*/
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/**
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* This class models a multicast UDP socket. A multicast address is a
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* class D internet address (one whose most significant bits are 1110).
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* A multicast group consists of a multicast address and a well known
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* port number. All members of the group listening on that address and
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* port will receive all the broadcasts to the group.
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* <p>
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* Please note that applets are not allowed to use multicast sockets
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*
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* Written using on-line Java Platform 1.2 API Specification, as well
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* as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998).
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* Status: Believed complete and correct.
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*
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* @author Warren Levy <warrenl@cygnus.com>
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* @author Aaron M. Renn (arenn@urbanophile.com) (Documentation comments)
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* @date May 18, 1999.
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*/
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public class MulticastSocket extends DatagramSocket
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{
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// FIXME: the local addr bound to the multicast socket can be reused;
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// unlike unicast sockets. It binds to any available network interface.
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// See p.1159 JCL book.
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/**
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* Create a MulticastSocket that this not bound to any address
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*
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* @exception IOException If an error occurs
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*/
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public MulticastSocket() throws IOException
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{
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super(0, ServerSocket.ANY_IF);
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}
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/**
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* Create a multicast socket bound to the specified port
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*
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* @param The port to bind to
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*
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* @exception IOException If an error occurs
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*/
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public MulticastSocket(int port) throws IOException
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{
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super(port, ServerSocket.ANY_IF);
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}
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/**
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* Returns the interface being used for multicast packets
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*
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* @return The multicast interface
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*
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* @exception SocketException If an error occurs
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*/
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public InetAddress getInterface() throws SocketException
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{
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// FIXME: Is it possible that an InetAddress wasn't returned from getOption?
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return (InetAddress) impl.getOption(SocketOptions.IP_MULTICAST_IF);
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}
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/**
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* Returns the current value of the "Time to Live" option. This is the
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* number of hops a packet can make before it "expires". This method id
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* deprecated. Use <code>getTimeToLive</code> instead.
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*
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* @return The TTL value
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*
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* @exception IOException If an error occurs
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*
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* @deprecated Replaced by getTimeToLive() in Java 1.2
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*/
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public byte getTTL() throws IOException
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{
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// Use getTTL here rather than getTimeToLive in case we're using an impl
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// other than the default PlainDatagramSocketImpl and it doesn't have
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// getTimeToLive yet.
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return impl.getTTL();
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}
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/**
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* Returns the current value of the "Time to Live" option. This is the
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* number of hops a packet can make before it "expires".
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*
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* @return The TTL value
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*
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* @exception IOException If an error occurs
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*
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* @since Java 1.2
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*/
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public int getTimeToLive() throws IOException
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{
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return impl.getTimeToLive();
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}
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/**
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* Sets the interface to use for multicast packets.
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*
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* @param addr The new interface to use
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*
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* @exception SocketException If an error occurs
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*/
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public void setInterface(InetAddress inf) throws SocketException
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{
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impl.setOption(SocketOptions.IP_MULTICAST_IF, inf);
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}
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/**
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* Sets the "Time to Live" value for a socket. The value must be between
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* 1 and 255.
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*
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* @param ttl The new TTL value
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*
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* @exception IOException If an error occurs
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*
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* @deprecated Replaced by <code>setTimeToLive</code> in Java 1.2
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*/
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public void setTTL(byte ttl) throws IOException
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{
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// Use setTTL here rather than setTimeToLive in case we're using an impl
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// other than the default PlainDatagramSocketImpl and it doesn't have
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// setTimeToLive yet.
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impl.setTTL(ttl);
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}
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/**
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* Sets the "Time to Live" value for a socket. The value must be between
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* 1 and 255.
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*
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* @param ttl The new TTL value
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*
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* @exception IOException If an error occurs
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*
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* @since Java 1.2
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*/
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public void setTimeToLive(int ttl) throws IOException
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{
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if (ttl <= 0 || ttl > 255)
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throw new IllegalArgumentException("Invalid ttl: " + ttl);
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impl.setTimeToLive(ttl);
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}
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/**
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* Joins the specified mulitcast group.
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*
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* @param addr The address of the group to join
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*
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* @exception IOException If an error occurs
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*/
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public void joinGroup(InetAddress mcastaddr) throws IOException
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{
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if (! mcastaddr.isMulticastAddress())
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throw new IOException("Not a Multicast address");
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SecurityManager s = System.getSecurityManager();
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if (s != null)
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s.checkMulticast(mcastaddr);
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impl.join(mcastaddr);
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}
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/**
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* Leaves the specified multicast group
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*
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* @param addr The address of the group to leave
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*
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* @exception IOException If an error occurs
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*/
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public void leaveGroup(InetAddress mcastaddr) throws IOException
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{
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if (! mcastaddr.isMulticastAddress())
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throw new IOException("Not a Multicast address");
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SecurityManager s = System.getSecurityManager();
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if (s != null)
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s.checkMulticast(mcastaddr);
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impl.leave(mcastaddr);
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}
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/**
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* Sends a packet of data to a multicast address with a TTL that is
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* different from the default TTL on this socket. The default TTL for
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* the socket is not changed.
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*
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* @param packet The packet of data to send
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* @param ttl The TTL for this packet
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*
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* @exception IOException If an error occurs
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*/
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public synchronized void send(DatagramPacket p, byte ttl) throws IOException
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{
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SecurityManager s = System.getSecurityManager();
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if (s != null)
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{
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InetAddress addr = p.getAddress();
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if (addr.isMulticastAddress())
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s.checkMulticast(addr, ttl);
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else
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s.checkConnect(addr.getHostAddress(), p.getPort());
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}
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int oldttl = impl.getTimeToLive();
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impl.setTimeToLive(((int) ttl) & 0xFF);
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impl.send(p);
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impl.setTimeToLive(oldttl);
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}
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} // class MulticastSocket
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