001 /* Selector.java -- 002 Copyright (C) 2002 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 import java.io.IOException; 041 import java.nio.channels.spi.SelectorProvider; 042 import java.util.Set; 043 044 045 /** 046 * @author Michael Koch 047 * @since 1.4 048 */ 049 public abstract class Selector 050 { 051 /** 052 * Initializes the selector. 053 */ 054 protected Selector() 055 { 056 } 057 058 /** 059 * Opens a selector. 060 * 061 * @exception IOException If an error occurs 062 */ 063 public static Selector open() throws IOException 064 { 065 return SelectorProvider.provider().openSelector(); 066 } 067 068 /** 069 * Closes the selector. 070 * 071 * @exception IOException If an error occurs 072 */ 073 public abstract void close() throws IOException; 074 075 /** 076 * Tells whether the selector is open or not. 077 */ 078 public abstract boolean isOpen(); 079 080 /** 081 * Returns this selector's key set. 082 * 083 * @exception ClosedSelectorException If this selector is closed. 084 */ 085 public abstract Set<SelectionKey> keys(); 086 087 /** 088 * Returns the SelectorProvider that created the selector. 089 */ 090 public abstract SelectorProvider provider(); 091 092 /** 093 * Selects a set of keys whose corresponding channels are ready 094 * for I/O operations. 095 * 096 * @exception ClosedSelectorException If this selector is closed. 097 * @exception IOException If an error occurs 098 */ 099 public abstract int select() throws IOException; 100 101 /** 102 * Selects a set of keys whose corresponding channels are ready 103 * for I/O operations. 104 * 105 * @param timeout The timeout to use. 106 * 107 * @exception ClosedSelectorException If this selector is closed. 108 * @exception IllegalArgumentException If the timeout value is negative. 109 * @exception IOException If an error occurs 110 */ 111 public abstract int select(long timeout) throws IOException; 112 113 /** 114 * Returns this selector's selected-key set. 115 * 116 * @exception ClosedSelectorException If this selector is closed. 117 */ 118 public abstract Set<SelectionKey> selectedKeys(); 119 120 /** 121 * Selects a set of keys whose corresponding channels are ready 122 * for I/O operations. 123 * 124 * @exception ClosedSelectorException If this selector is closed. 125 * @exception IOException If an error occurs 126 */ 127 public abstract int selectNow() throws IOException; 128 129 /** 130 * Causes the first selection operation that has not yet returned to 131 * return immediately. 132 */ 133 public abstract Selector wakeup(); 134 }