Source code: 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., 51 Franklin Street, Fifth Floor, Boston, MA
20 02110-1301 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 }