001 /* SelectionKey.java -- 002 Copyright (C) 2002, 2006 Free Software Foundation, Inc. 003 004 This file is part of GNU Classpath. 005 006 GNU Classpath is free software; you can redistribute it and/or modify 007 it under the terms of the GNU General Public License as published by 008 the Free Software Foundation; either version 2, or (at your option) 009 any later version. 010 011 GNU Classpath is distributed in the hope that it will be useful, but 012 WITHOUT ANY WARRANTY; without even the implied warranty of 013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014 General Public License for more details. 015 016 You should have received a copy of the GNU General Public License 017 along with GNU Classpath; see the file COPYING. If not, write to the 018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 019 02110-1301 USA. 020 021 Linking this library statically or dynamically with other modules is 022 making a combined work based on this library. Thus, the terms and 023 conditions of the GNU General Public License cover the whole 024 combination. 025 026 As a special exception, the copyright holders of this library give you 027 permission to link this library with independent modules to produce an 028 executable, regardless of the license terms of these independent 029 modules, and to copy and distribute the resulting executable under 030 terms of your choice, provided that you also meet, for each linked 031 independent module, the terms and conditions of the license of that 032 module. An independent module is a module which is not derived from 033 or based on this library. If you modify this library, you may extend 034 this exception to your version of the library, but you are not 035 obligated to do so. If you do not wish to do so, delete this 036 exception statement from your version. */ 037 038 package java.nio.channels; 039 040 041 /** 042 * @author Michael Koch 043 * @since 1.4 044 */ 045 public abstract class SelectionKey 046 { 047 public static final int OP_ACCEPT = 16; 048 public static final int OP_CONNECT = 8; 049 public static final int OP_READ = 1; 050 public static final int OP_WRITE = 4; 051 Object attached; 052 053 /** 054 * Initializes the selection key. 055 */ 056 protected SelectionKey() 057 { 058 } 059 060 /** 061 * Attaches obj to the key and returns the old attached object. 062 */ 063 public final synchronized Object attach(Object obj) 064 { 065 Object old = attached; 066 attached = obj; 067 return old; 068 } 069 070 /** 071 * Returns the object attached to the key. 072 */ 073 public final synchronized Object attachment() 074 { 075 return attached; 076 } 077 078 /** 079 * Tests if the channel attached to this key is ready to accept 080 * a new socket connection. 081 * 082 * @exception CancelledKeyException If this key has been cancelled 083 */ 084 public final boolean isAcceptable() 085 { 086 return (readyOps() & OP_ACCEPT) != 0; 087 } 088 089 /** 090 * Tests whether this key's channel has either finished, 091 * or failed to finish, its socket-connection operation. 092 * 093 * @exception CancelledKeyException If this key has been cancelled 094 */ 095 public final boolean isConnectable() 096 { 097 return (readyOps() & OP_CONNECT) != 0; 098 } 099 100 /** 101 * Tests if the channel attached to the key is readable. 102 * 103 * @exception CancelledKeyException If this key has been cancelled 104 */ 105 public final boolean isReadable() 106 { 107 return (readyOps() & OP_READ) != 0; 108 } 109 110 /** 111 * Tests if the channel attached to the key is writable. 112 * 113 * @exception CancelledKeyException If this key has been cancelled 114 */ 115 public final boolean isWritable() 116 { 117 return (readyOps() & OP_WRITE) != 0; 118 } 119 120 /** 121 * Requests that the registration of this key's channel with 122 * its selector be cancelled. 123 */ 124 public abstract void cancel(); 125 126 /** 127 * return the channel attached to the key. 128 */ 129 public abstract SelectableChannel channel(); 130 131 /** 132 * Returns the key's interest set. 133 * 134 * @exception CancelledKeyException If this key has been cancelled 135 */ 136 public abstract int interestOps(); 137 138 /** 139 * Sets this key's interest set to the given value. 140 * 141 * @exception CancelledKeyException If this key has been cancelled 142 * @exception IllegalArgumentException If a bit in the set does not 143 * correspond to an operation that is supported by this key's channel, 144 * that is, if set & ~(channel().validOps()) != 0 145 */ 146 public abstract SelectionKey interestOps(int ops); 147 148 /** 149 * Tells whether or not this key is valid. 150 */ 151 public abstract boolean isValid(); 152 153 /** 154 * Retrieves this key's ready-operation set. 155 * 156 * @exception CancelledKeyException If this key has been cancelled 157 */ 158 public abstract int readyOps(); 159 160 /** 161 * Returns the selector for which this key was created. 162 */ 163 public abstract Selector selector(); 164 }