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 package java.net;
  40
  41 import java.io.FileDescriptor;
  42 import java.io.IOException;
  43
  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    * The local port to which this socket is bound
  63    */
  64   protected int localPort;
  65
  66   /**
  67    * The FileDescriptor object for this object.
  68    */
  69   protected FileDescriptor fd;
  70
  71   /**
  72    * Default, no-argument constructor for subclasses to call.
  73    */
  74   public DatagramSocketImpl()
  75   {
  76   }
  77
  78   /**
  79    * This method binds the socket to the specified local port and address.
  80    *
  81    * @param lport The port number to bind to
  82    * @param laddr The address to bind to
  83    *
  84    * @exception SocketException If an error occurs
  85    */
  86   protected abstract void bind(int lport, InetAddress laddr)
  87     throws SocketException;
  88
  89   /**
  90    * This methods closes the socket
  91    */
  92   protected abstract void close();
  93
  94   /**
  95    * Creates a new datagram socket.
  96    *
  97    * @exception SocketException If an error occurs
  98    */
  99   protected abstract void create() throws SocketException;
 100
 101   /**
 102    * Takes a peek at the next packet received in order to retrieve the
 103    * address of the sender
 104    *
 105    * @param i The <code>InetAddress</code> to fill in with the information
 106    *          about the sender if the next packet
 107    *
 108    * @return The port number of the sender of the packet
 109    *
 110    * @exception IOException If an error occurs
 111    * @exception PortUnreachableException May be thrown if the socket is
 112    * connected to a currently unreachable destination. Note, there is no
 113    * guarantee that the exception will be thrown.
 114    */
 115   protected abstract int peek(InetAddress i) throws IOException;
 116
 117   /**
 118    * Takes a peek at the next packet received.  This packet is not consumed.
 119    * With the next peekData/receive operation this packet will be read again.
 120    *
 121    * @param p The <code>DatagramPacket</code> to fill in with the data sent.
 122    *
 123    * @return The port number of the sender of the packet.
 124    *
 125    * @exception IOException If an error occurs
 126    * @exception PortUnreachableException May be thrown if the socket is
 127    * connected to a currently unreachable destination. Note, there is no
 128    * guarantee that the exception will be thrown.
 129    *
 130    * @since 1.4
 131    */
 132   protected abstract int peekData(DatagramPacket p) throws IOException;
 133
 134   /**
 135    * Transmits the specified packet of data to the network.  The destination
 136    * host and port should be encoded in the packet.
 137    *
 138    * @param p The packet to send
 139    *
 140    * @exception IOException If an error occurs
 141    * @exception PortUnreachableException May be thrown if the socket is
 142    * connected to a currently unreachable destination. Note, there is no
 143    * guarantee that the exception will be thrown.
 144    */
 145   protected abstract void send(DatagramPacket p) throws IOException;
 146
 147   /**
 148    * Receives a packet of data from the network  Will block until a packet
 149    * arrives.  The packet info in populated into the passed in
 150    * <code>DatagramPacket</code> object.
 151    *
 152    * @param p A place to store the incoming packet.
 153    *
 154    * @exception IOException If an error occurs
 155    * @exception PortUnreachableException May be thrown if the socket is
 156    * connected to a currently unreachable destination. Note, there is no
 157    * guarantee that the exception will be thrown.
 158    */
 159   protected abstract void receive(DatagramPacket p) throws IOException;
 160
 161   /**
 162    * Connects the socket to a host specified by address and port.
 163    *
 164    * @param address The <code>InetAddress</code> of the host to connect to
 165    * @param port The port number of the host to connect to
 166    *
 167    * @exception SocketException If an error occurs
 168    *
 169    * @since 1.4
 170    */
 171   protected void connect(InetAddress address, int port)
 172     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    * @return the current time-to-live
 203    *
 204    * @exception IOException If an error occurs
 205    *
 206    * @deprecated // FIXME: when ?
 207    */
 208   protected abstract byte getTTL() throws IOException;
 209
 210   /**
 211    * Sets the Time to Live (TTL) setting on this socket to the specified
 212    * value.
 213    *
 214    * @param ttl The new Time to Live value
 215    *
 216    * @exception IOException If an error occurs
 217    */
 218   protected abstract void setTimeToLive(int ttl) throws IOException;
 219
 220   /**
 221    * This method returns the current Time to Live (TTL) setting on this
 222    * socket.
 223    *
 224    * @return the current time-to-live
 225    *
 226    * @exception IOException If an error occurs
 227    */
 228   protected abstract int getTimeToLive() throws IOException;
 229
 230   /**
 231    * Causes this socket to join the specified multicast group
 232    *
 233    * @param inetaddr The multicast address to join with
 234    *
 235    * @exception IOException If an error occurs
 236    */
 237   protected abstract void join(InetAddress inetaddr) throws IOException;
 238
 239   /**
 240    * Causes the socket to leave the specified multicast group.
 241    *
 242    * @param inetaddr The multicast address to leave
 243    *
 244    * @exception IOException If an error occurs
 245    */
 246   protected abstract void leave(InetAddress inetaddr) throws IOException;
 247
 248   /**
 249    * Causes this socket to join the specified multicast group on a specified
 250    * device
 251    *
 252    * @param mcastaddr The address to leave
 253    * @param netIf The specified network interface to join the group at
 254    *
 255    * @exception IOException If an error occurs
 256    *
 257    * @since 1.4
 258    */
 259   protected abstract void joinGroup(SocketAddress mcastaddr,
 260                                     NetworkInterface netIf)
 261     throws IOException;
 262
 263   /**
 264    * Leaves a multicast group
 265    *
 266    * @param mcastaddr The address to join
 267    * @param netIf The specified network interface to leave the group at
 268    *
 269    * @exception IOException If an error occurs
 270    *
 271    * @since 1.4
 272    */
 273   protected abstract void leaveGroup(SocketAddress mcastaddr,
 274                                      NetworkInterface netIf)
 275     throws IOException;
 276
 277   /**
 278    * Returns the FileDescriptor for this socket
 279    *
 280    * @return the file descriptor associated with this socket
 281    */
 282   protected FileDescriptor getFileDescriptor()
 283   {
 284     return fd;
 285   }
 286
 287   /**
 288    * Returns the local port this socket is bound to
 289    *
 290    * @return the local port
 291    */
 292   protected int getLocalPort()
 293   {
 294     return localPort;
 295   }
 296 }