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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: }