J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000-2001 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.nio.channels; |
| 27 | |
| 28 | import java.io.IOException; |
| 29 | import java.nio.channels.spi.*; |
| 30 | |
| 31 | |
| 32 | /** |
| 33 | * A pair of channels that implements a unidirectional pipe. |
| 34 | * |
| 35 | * <p> A pipe consists of a pair of channels: A writable {@link |
| 36 | * Pipe.SinkChannel </code>sink<code>} channel and a readable {@link |
| 37 | * Pipe.SourceChannel </code>source<code>} channel. Once some bytes are |
| 38 | * written to the sink channel they can be read from source channel in exactly |
| 39 | * the order in which they were written. |
| 40 | * |
| 41 | * <p> Whether or not a thread writing bytes to a pipe will block until another |
| 42 | * thread reads those bytes, or some previously-written bytes, from the pipe is |
| 43 | * system-dependent and therefore unspecified. Many pipe implementations will |
| 44 | * buffer up to a certain number of bytes between the sink and source channels, |
| 45 | * but such buffering should not be assumed. </p> |
| 46 | * |
| 47 | * |
| 48 | * @author Mark Reinhold |
| 49 | * @author JSR-51 Expert Group |
| 50 | * @since 1.4 |
| 51 | */ |
| 52 | |
| 53 | public abstract class Pipe { |
| 54 | |
| 55 | /** |
| 56 | * A channel representing the readable end of a {@link Pipe}. </p> |
| 57 | * |
| 58 | * @since 1.4 |
| 59 | */ |
| 60 | public static abstract class SourceChannel |
| 61 | extends AbstractSelectableChannel |
| 62 | implements ReadableByteChannel, ScatteringByteChannel |
| 63 | { |
| 64 | /** |
| 65 | * Constructs a new instance of this class. |
| 66 | */ |
| 67 | protected SourceChannel(SelectorProvider provider) { |
| 68 | super(provider); |
| 69 | } |
| 70 | |
| 71 | /** |
| 72 | * Returns an operation set identifying this channel's supported |
| 73 | * operations. |
| 74 | * |
| 75 | * <p> Pipe-source channels only support reading, so this method |
| 76 | * returns {@link SelectionKey#OP_READ}. </p> |
| 77 | * |
| 78 | * @return The valid-operation set |
| 79 | */ |
| 80 | public final int validOps() { |
| 81 | return SelectionKey.OP_READ; |
| 82 | } |
| 83 | |
| 84 | } |
| 85 | |
| 86 | /** |
| 87 | * A channel representing the writable end of a {@link Pipe}. </p> |
| 88 | * |
| 89 | * @since 1.4 |
| 90 | */ |
| 91 | public static abstract class SinkChannel |
| 92 | extends AbstractSelectableChannel |
| 93 | implements WritableByteChannel, GatheringByteChannel |
| 94 | { |
| 95 | /** |
| 96 | * Initializes a new instance of this class. |
| 97 | */ |
| 98 | protected SinkChannel(SelectorProvider provider) { |
| 99 | super(provider); |
| 100 | } |
| 101 | |
| 102 | /** |
| 103 | * Returns an operation set identifying this channel's supported |
| 104 | * operations. |
| 105 | * |
| 106 | * <p> Pipe-sink channels only support writing, so this method returns |
| 107 | * {@link SelectionKey#OP_WRITE}. </p> |
| 108 | * |
| 109 | * @return The valid-operation set |
| 110 | */ |
| 111 | public final int validOps() { |
| 112 | return SelectionKey.OP_WRITE; |
| 113 | } |
| 114 | |
| 115 | } |
| 116 | |
| 117 | /** |
| 118 | * Initializes a new instance of this class. |
| 119 | */ |
| 120 | protected Pipe() { } |
| 121 | |
| 122 | /** |
| 123 | * Returns this pipe's source channel. </p> |
| 124 | * |
| 125 | * @return This pipe's source channel |
| 126 | */ |
| 127 | public abstract SourceChannel source(); |
| 128 | |
| 129 | /** |
| 130 | * Returns this pipe's sink channel. </p> |
| 131 | * |
| 132 | * @return This pipe's sink channel |
| 133 | */ |
| 134 | public abstract SinkChannel sink(); |
| 135 | |
| 136 | /** |
| 137 | * Opens a pipe. |
| 138 | * |
| 139 | * <p> The new pipe is created by invoking the {@link |
| 140 | * java.nio.channels.spi.SelectorProvider#openPipe openPipe} method of the |
| 141 | * system-wide default {@link java.nio.channels.spi.SelectorProvider} |
| 142 | * object. </p> |
| 143 | * |
| 144 | * @return A new pipe |
| 145 | * |
| 146 | * @throws IOException |
| 147 | * If an I/O error occurs |
| 148 | */ |
| 149 | public static Pipe open() throws IOException { |
| 150 | return SelectorProvider.provider().openPipe(); |
| 151 | } |
| 152 | |
| 153 | } |