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 }