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| 1 | +/* | |
| 2 | + * Copyright (c) 1996, 2006, Oracle and/or its affiliates. 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. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | + | |
| 26 | +package java.io; | |
| 27 | + | |
| 28 | + | |
| 29 | +/** | |
| 30 | + * Piped character-output streams. | |
| 31 | + * | |
| 32 | + * @author Mark Reinhold | |
| 33 | + * @since JDK1.1 | |
| 34 | + */ | |
| 35 | + | |
| 36 | +public class PipedWriter extends Writer { | |
| 37 | + | |
| 38 | + /* REMIND: identification of the read and write sides needs to be | |
| 39 | + more sophisticated. Either using thread groups (but what about | |
| 40 | + pipes within a thread?) or using finalization (but it may be a | |
| 41 | + long time until the next GC). */ | |
| 42 | + private PipedReader sink; | |
| 43 | + | |
| 44 | + /* This flag records the open status of this particular writer. It | |
| 45 | + * is independent of the status flags defined in PipedReader. It is | |
| 46 | + * used to do a sanity check on connect. | |
| 47 | + */ | |
| 48 | + private boolean closed = false; | |
| 49 | + | |
| 50 | + /** | |
| 51 | + * Creates a piped writer connected to the specified piped | |
| 52 | + * reader. Data characters written to this stream will then be | |
| 53 | + * available as input from <code>snk</code>. | |
| 54 | + * | |
| 55 | + * @param snk The piped reader to connect to. | |
| 56 | + * @exception IOException if an I/O error occurs. | |
| 57 | + */ | |
| 58 | + public PipedWriter(PipedReader snk) throws IOException { | |
| 59 | + connect(snk); | |
| 60 | + } | |
| 61 | + | |
| 62 | + /** | |
| 63 | + * Creates a piped writer that is not yet connected to a | |
| 64 | + * piped reader. It must be connected to a piped reader, | |
| 65 | + * either by the receiver or the sender, before being used. | |
| 66 | + * | |
| 67 | + * @see java.io.PipedReader#connect(java.io.PipedWriter) | |
| 68 | + * @see java.io.PipedWriter#connect(java.io.PipedReader) | |
| 69 | + */ | |
| 70 | + public PipedWriter() { | |
| 71 | + } | |
| 72 | + | |
| 73 | + /** | |
| 74 | + * Connects this piped writer to a receiver. If this object | |
| 75 | + * is already connected to some other piped reader, an | |
| 76 | + * <code>IOException</code> is thrown. | |
| 77 | + * <p> | |
| 78 | + * If <code>snk</code> is an unconnected piped reader and | |
| 79 | + * <code>src</code> is an unconnected piped writer, they may | |
| 80 | + * be connected by either the call: | |
| 81 | + * <blockquote><pre> | |
| 82 | + * src.connect(snk)</pre></blockquote> | |
| 83 | + * or the call: | |
| 84 | + * <blockquote><pre> | |
| 85 | + * snk.connect(src)</pre></blockquote> | |
| 86 | + * The two calls have the same effect. | |
| 87 | + * | |
| 88 | + * @param snk the piped reader to connect to. | |
| 89 | + * @exception IOException if an I/O error occurs. | |
| 90 | + */ | |
| 91 | + public synchronized void connect(PipedReader snk) throws IOException { | |
| 92 | + if (snk == null) { | |
| 93 | + throw new NullPointerException(); | |
| 94 | + } else if (sink != null || snk.connected) { | |
| 95 | + throw new IOException("Already connected"); | |
| 96 | + } else if (snk.closedByReader || closed) { | |
| 97 | + throw new IOException("Pipe closed"); | |
| 98 | + } | |
| 99 | + | |
| 100 | + sink = snk; | |
| 101 | + snk.in = -1; | |
| 102 | + snk.out = 0; | |
| 103 | + snk.connected = true; | |
| 104 | + } | |
| 105 | + | |
| 106 | + /** | |
| 107 | + * Writes the specified <code>char</code> to the piped output stream. | |
| 108 | + * If a thread was reading data characters from the connected piped input | |
| 109 | + * stream, but the thread is no longer alive, then an | |
| 110 | + * <code>IOException</code> is thrown. | |
| 111 | + * <p> | |
| 112 | + * Implements the <code>write</code> method of <code>Writer</code>. | |
| 113 | + * | |
| 114 | + * @param c the <code>char</code> to be written. | |
| 115 | + * @exception IOException if the pipe is | |
| 116 | + * <a href=PipedOutputStream.html#BROKEN> <code>broken</code></a>, | |
| 117 | + * {@link #connect(java.io.PipedReader) unconnected}, closed | |
| 118 | + * or an I/O error occurs. | |
| 119 | + */ | |
| 120 | + public void write(int c) throws IOException { | |
| 121 | + if (sink == null) { | |
| 122 | + throw new IOException("Pipe not connected"); | |
| 123 | + } | |
| 124 | + sink.receive(c); | |
| 125 | + } | |
| 126 | + | |
| 127 | + /** | |
| 128 | + * Writes <code>len</code> characters from the specified character array | |
| 129 | + * starting at offset <code>off</code> to this piped output stream. | |
| 130 | + * This method blocks until all the characters are written to the output | |
| 131 | + * stream. | |
| 132 | + * If a thread was reading data characters from the connected piped input | |
| 133 | + * stream, but the thread is no longer alive, then an | |
| 134 | + * <code>IOException</code> is thrown. | |
| 135 | + * | |
| 136 | + * @param cbuf the data. | |
| 137 | + * @param off the start offset in the data. | |
| 138 | + * @param len the number of characters to write. | |
| 139 | + * @exception IOException if the pipe is | |
| 140 | + * <a href=PipedOutputStream.html#BROKEN> <code>broken</code></a>, | |
| 141 | + * {@link #connect(java.io.PipedReader) unconnected}, closed | |
| 142 | + * or an I/O error occurs. | |
| 143 | + */ | |
| 144 | + public void write(char cbuf[], int off, int len) throws IOException { | |
| 145 | + if (sink == null) { | |
| 146 | + throw new IOException("Pipe not connected"); | |
| 147 | + } else if ((off | len | (off + len) | (cbuf.length - (off + len))) < 0) { | |
| 148 | + throw new IndexOutOfBoundsException(); | |
| 149 | + } | |
| 150 | + sink.receive(cbuf, off, len); | |
| 151 | + } | |
| 152 | + | |
| 153 | + /** | |
| 154 | + * Flushes this output stream and forces any buffered output characters | |
| 155 | + * to be written out. | |
| 156 | + * This will notify any readers that characters are waiting in the pipe. | |
| 157 | + * | |
| 158 | + * @exception IOException if the pipe is closed, or an I/O error occurs. | |
| 159 | + */ | |
| 160 | + public synchronized void flush() throws IOException { | |
| 161 | + if (sink != null) { | |
| 162 | + if (sink.closedByReader || closed) { | |
| 163 | + throw new IOException("Pipe closed"); | |
| 164 | + } | |
| 165 | + synchronized (sink) { | |
| 166 | + sink.notifyAll(); | |
| 167 | + } | |
| 168 | + } | |
| 169 | + } | |
| 170 | + | |
| 171 | + /** | |
| 172 | + * Closes this piped output stream and releases any system resources | |
| 173 | + * associated with this stream. This stream may no longer be used for | |
| 174 | + * writing characters. | |
| 175 | + * | |
| 176 | + * @exception IOException if an I/O error occurs. | |
| 177 | + */ | |
| 178 | + public void close() throws IOException { | |
| 179 | + closed = true; | |
| 180 | + if (sink != null) { | |
| 181 | + sink.receivedLast(); | |
| 182 | + } | |
| 183 | + } | |
| 184 | +} | |