libjava/java/net/DatagramSocketImpl.java

   1 /* DatagramSocketImpl.java -- Abstract class for UDP socket implementations
   2    Copyright (C) 1998, 1999 2000, 2001,
   3                  2002, 2003 Free Software Foundation, Inc.
   4
   5 This file is part of GNU Classpath.
   6
   7 GNU Classpath is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU Classpath is distributed in the hope that it will be useful, but
  13 WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Classpath; see the file COPYING.  If not, write to the
  19 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20 02111-1307 USA.
  21
  22 Linking this library statically or dynamically with other modules is
  23 making a combined work based on this library.  Thus, the terms and
  24 conditions of the GNU General Public License cover the whole
  25 combination.
  26
  27 As a special exception, the copyright holders of this library give you
  28 permission to link this library with independent modules to produce an
  29 executable, regardless of the license terms of these independent
  30 modules, and to copy and distribute the resulting executable under
  31 terms of your choice, provided that you also meet, for each linked
  32 independent module, the terms and conditions of the license of that
  33 module.  An independent module is a module which is not derived from
  34 or based on this library.  If you modify this library, you may extend
  35 this exception to your version of the library, but you are not
  36 obligated to do so.  If you do not wish to do so, delete this
  37 exception statement from your version. */
  38
  39
  40 package java.net;
  41
  42 import java.io.IOException;
  43 import java.io.FileDescriptor;
  44
  45 /**
  46  * This abstract class models a datagram socket implementation.  An
  47  * actual implementation class would implement these methods, probably
  48  * via redirecting them to native code.
  49  * <p>
  50  * Written using on-line Java Platform 1.2 API Specification, as well
  51  * as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998).
  52  * <p>
  53  * Status:  Believed complete and correct.
  54  *
  55  * @author Aaron M. Renn (arenn@urbanophile.com)
  56  * @author Warren Levy <warrenl@cygnus.com>
  57  * @since 1.1
  58  */
  59 public abstract class DatagramSocketImpl implements SocketOptions
  60 {
  61
  62   /**
  63    * The local port to which this socket is bound
  64    */
  65   protected int localPort;
  66
  67   /**
  68    * The FileDescriptor object for this object.
  69    */
  70   protected FileDescriptor fd;
  71
  72   /**
  73    * Default, no-argument constructor for subclasses to call.
  74    */
  75   public DatagramSocketImpl()
  76   {
  77   }
  78
  79   /**
  80    * This method binds the socket to the specified local port and address.
  81    *
  82    * @param lport The port number to bind to
  83    * @param laddr The address to bind to
  84    *
  85    * @exception SocketException If an error occurs
  86    */
  87   protected abstract void bind(int lport, InetAddress laddr)
  88     throws SocketException;
  89
  90   /**
  91    * This methods closes the socket
  92    */
  93   protected abstract void close();
  94
  95   /**
  96    * Creates a new datagram socket.
  97    *
  98    * @exception SocketException If an error occurs
  99    */
 100   protected abstract void create() throws SocketException;
 101
 102   /**
 103    * Takes a peek at the next packet received in order to retrieve the
 104    * address of the sender
 105    *
 106    * @param i The <code>InetAddress</code> to fill in with the information
 107    *          about the sender if the next packet
 108    *
 109    * @return The port number of the sender of the packet
 110    *
 111    * @exception IOException If an error occurs
 112    * @exception PortUnreachableException May be thrown if the socket is
 113    * connected to a currently unreachable destination. Note, there is no
 114    * guarantee that the exception will be thrown.
 115    */
 116   protected abstract int peek(InetAddress i) throws IOException;
 117
 118   /**
 119    * Takes a peek at the next packet received.  This packet is not consumed.
 120    * With the next peekData/receive operation this packet will be read again.
 121    *
 122    * @param p The <code>DatagramPacket</code> to fill in with the data sent.
 123    *
 124    * @return The port number of the sender of the packet.
 125    *
 126    * @exception IOException If an error occurs
 127    * @exception PortUnreachableException May be thrown if the socket is
 128    * connected to a currently unreachable destination. Note, there is no
 129    * guarantee that the exception will be thrown.
 130    *
 131    * @since 1.4
 132    */
 133   protected abstract int peekData (DatagramPacket p) throws IOException;
 134
 135   /**
 136    * Transmits the specified packet of data to the network.  The destination
 137    * host and port should be encoded in the packet.
 138    *
 139    * @param p The packet to send
 140    *
 141    * @exception IOException If an error occurs
 142    * @exception PortUnreachableException May be thrown if the socket is
 143    * connected to a currently unreachable destination. Note, there is no
 144    * guarantee that the exception will be thrown.
 145    */
 146   protected abstract void send(DatagramPacket p) throws IOException;
 147
 148   /**
 149    * Receives a packet of data from the network  Will block until a packet
 150    * arrives.  The packet info in populated into the passed in
 151    * <code>DatagramPacket</code> object.
 152    *
 153    * @param p A place to store the incoming packet.
 154    *
 155    * @exception IOException If an error occurs
 156    * @exception PortUnreachableException May be thrown if the socket is
 157    * connected to a currently unreachable destination. Note, there is no
 158    * guarantee that the exception will be thrown.
 159    */
 160   protected abstract void receive(DatagramPacket p) throws IOException;
 161
 162   /**
 163    * Connects the socket to a host specified by address and port.
 164    *
 165    * @param address The <code>InetAddress</code> of the host to connect to
 166    * @param port The port number of the host to connect to
 167    *
 168    * @exception SocketException If an error occurs
 169    *
 170    * @since 1.4
 171    */
 172   protected void connect (InetAddress address, int port) throws SocketException
 173   {
 174     // This method has to be overwritten by real implementations
 175   }
 176
 177   /**
 178    * Disconnects the socket.
 179    *
 180    * @since 1.4
 181    */
 182   protected void disconnect ()
 183   {
 184     // This method has to be overwritten by real implementations
 185   }
 186
 187   /**
 188    * Sets the Time to Live (TTL) setting on this socket to the specified
 189    * value. <b>Use <code>setTimeToLive(int)</code></b> instead.
 190    *
 191    * @param ttl The new Time to Live value
 192    *
 193    * @exception IOException If an error occurs
 194    * @deprecated
 195    */
 196   protected abstract void setTTL(byte ttl) throws IOException;
 197
 198   /**
 199    * This method returns the current Time to Live (TTL) setting on this
 200    * socket.  <b>Use <code>getTimeToLive()</code></b> instead.
 201    *
 202    * @exception IOException If an error occurs
 203    * @deprecated
 204    */
 205   protected abstract byte getTTL() throws IOException;
 206
 207   /**
 208    * Sets the Time to Live (TTL) setting on this socket to the specified
 209    * value.
 210    *
 211    * @param ttl The new Time to Live value
 212    *
 213    * @exception IOException If an error occurs
 214    */
 215   protected abstract void setTimeToLive(int ttl) throws IOException;
 216
 217   /**
 218    * This method returns the current Time to Live (TTL) setting on this
 219    * socket.
 220    *
 221    * @exception IOException If an error occurs
 222    */
 223   protected abstract int getTimeToLive() throws IOException;
 224
 225   /**
 226    * Causes this socket to join the specified multicast group
 227    *
 228    * @param inetaddr The multicast address to join with
 229    *
 230    * @exception IOException If an error occurs
 231    */
 232   protected abstract void join(InetAddress inetaddr) throws IOException;
 233
 234   /**
 235    * Causes the socket to leave the specified multicast group.
 236    *
 237    * @param inetaddr The multicast address to leave
 238    *
 239    * @exception IOException If an error occurs
 240    */
 241   protected abstract void leave(InetAddress inetaddr) throws IOException;
 242
 243   /**
 244    * Causes this socket to join the specified multicast group on a specified
 245    * device
 246    *
 247    * @param mcastaddr The address to leave
 248    * @param netIf The specified network interface to join the group at
 249    *
 250    * @exception IOException If an error occurs
 251    *
 252    * @since 1.4
 253    */
 254   protected abstract void joinGroup (SocketAddress mcastaddr,
 255                                      NetworkInterface netIf)
 256     throws IOException;
 257
 258   /**
 259    * Leaves a multicast group
 260    *
 261    * @param mcastaddr The address to join
 262    * @param netIf The specified network interface to leave the group at
 263    *
 264    * @exception IOException If an error occurs
 265    *
 266    * @since 1.4
 267    */
 268   protected abstract void leaveGroup (SocketAddress mcastaddr,
 269                                       NetworkInterface netIf)
 270     throws IOException;
 271
 272   /**
 273    * Returns the FileDescriptor for this socket
 274    */
 275   protected FileDescriptor getFileDescriptor()
 276   {
 277     return fd;
 278   }
 279
 280   /**
 281    * Returns the local port this socket is bound to
 282    */
 283   protected int getLocalPort()
 284   {
 285     return localPort;
 286   }
 287 }