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My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

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java/pkg/java/io/PipedReader.java+363−0
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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-input streams.
31+ *
32+ * @author Mark Reinhold
33+ * @since JDK1.1
34+ */
35+
36+public class PipedReader extends Reader {
37+ boolean closedByWriter = false;
38+ boolean closedByReader = false;
39+ boolean connected = false;
40+
41+ /* REMIND: identification of the read and write sides needs to be
42+ more sophisticated. Either using thread groups (but what about
43+ pipes within a thread?) or using finalization (but it may be a
44+ long time until the next GC). */
45+ Thread readSide;
46+ Thread writeSide;
47+
48+ /**
49+ * The size of the pipe's circular input buffer.
50+ */
51+ private static final int DEFAULT_PIPE_SIZE = 1024;
52+
53+ /**
54+ * The circular buffer into which incoming data is placed.
55+ */
56+ char buffer[];
57+
58+ /**
59+ * The index of the position in the circular buffer at which the
60+ * next character of data will be stored when received from the connected
61+ * piped writer. <code>in&lt;0</code> implies the buffer is empty,
62+ * <code>in==out</code> implies the buffer is full
63+ */
64+ int in = -1;
65+
66+ /**
67+ * The index of the position in the circular buffer at which the next
68+ * character of data will be read by this piped reader.
69+ */
70+ int out = 0;
71+
72+ /**
73+ * Creates a <code>PipedReader</code> so
74+ * that it is connected to the piped writer
75+ * <code>src</code>. Data written to <code>src</code>
76+ * will then be available as input from this stream.
77+ *
78+ * @param src the stream to connect to.
79+ * @exception IOException if an I/O error occurs.
80+ */
81+ public PipedReader(PipedWriter src) throws IOException {
82+ this(src, DEFAULT_PIPE_SIZE);
83+ }
84+
85+ /**
86+ * Creates a <code>PipedReader</code> so that it is connected
87+ * to the piped writer <code>src</code> and uses the specified
88+ * pipe size for the pipe's buffer. Data written to <code>src</code>
89+ * will then be available as input from this stream.
90+
91+ * @param src the stream to connect to.
92+ * @param pipeSize the size of the pipe's buffer.
93+ * @exception IOException if an I/O error occurs.
94+ * @exception IllegalArgumentException if <code>pipeSize <= 0</code>.
95+ * @since 1.6
96+ */
97+ public PipedReader(PipedWriter src, int pipeSize) throws IOException {
98+ initPipe(pipeSize);
99+ connect(src);
100+ }
101+
102+
103+ /**
104+ * Creates a <code>PipedReader</code> so
105+ * that it is not yet {@linkplain #connect(java.io.PipedWriter)
106+ * connected}. It must be {@linkplain java.io.PipedWriter#connect(
107+ * java.io.PipedReader) connected} to a <code>PipedWriter</code>
108+ * before being used.
109+ */
110+ public PipedReader() {
111+ initPipe(DEFAULT_PIPE_SIZE);
112+ }
113+
114+ /**
115+ * Creates a <code>PipedReader</code> so that it is not yet
116+ * {@link #connect(java.io.PipedWriter) connected} and uses
117+ * the specified pipe size for the pipe's buffer.
118+ * It must be {@linkplain java.io.PipedWriter#connect(
119+ * java.io.PipedReader) connected} to a <code>PipedWriter</code>
120+ * before being used.
121+ *
122+ * @param pipeSize the size of the pipe's buffer.
123+ * @exception IllegalArgumentException if <code>pipeSize <= 0</code>.
124+ * @since 1.6
125+ */
126+ public PipedReader(int pipeSize) {
127+ initPipe(pipeSize);
128+ }
129+
130+ private void initPipe(int pipeSize) {
131+ if (pipeSize <= 0) {
132+ throw new IllegalArgumentException("Pipe size <= 0");
133+ }
134+ buffer = new char[pipeSize];
135+ }
136+
137+ /**
138+ * Causes this piped reader to be connected
139+ * to the piped writer <code>src</code>.
140+ * If this object is already connected to some
141+ * other piped writer, an <code>IOException</code>
142+ * is thrown.
143+ * <p>
144+ * If <code>src</code> is an
145+ * unconnected piped writer and <code>snk</code>
146+ * is an unconnected piped reader, they
147+ * may be connected by either the call:
148+ * <p>
149+ * <pre><code>snk.connect(src)</code> </pre>
150+ * <p>
151+ * or the call:
152+ * <p>
153+ * <pre><code>src.connect(snk)</code> </pre>
154+ * <p>
155+ * The two
156+ * calls have the same effect.
157+ *
158+ * @param src The piped writer to connect to.
159+ * @exception IOException if an I/O error occurs.
160+ */
161+ public void connect(PipedWriter src) throws IOException {
162+ src.connect(this);
163+ }
164+
165+ /**
166+ * Receives a char of data. This method will block if no input is
167+ * available.
168+ */
169+ synchronized void receive(int c) throws IOException {
170+ if (!connected) {
171+ throw new IOException("Pipe not connected");
172+ } else if (closedByWriter || closedByReader) {
173+ throw new IOException("Pipe closed");
174+ } else if (readSide != null && !readSide.isAlive()) {
175+ throw new IOException("Read end dead");
176+ }
177+
178+ writeSide = Thread.currentThread();
179+ while (in == out) {
180+ if ((readSide != null) && !readSide.isAlive()) {
181+ throw new IOException("Pipe broken");
182+ }
183+ /* full: kick any waiting readers */
184+ notifyAll();
185+ try {
186+ wait(1000);
187+ } catch (InterruptedException ex) {
188+ throw new java.io.InterruptedIOException();
189+ }
190+ }
191+ if (in < 0) {
192+ in = 0;
193+ out = 0;
194+ }
195+ buffer[in++] = (char) c;
196+ if (in >= buffer.length) {
197+ in = 0;
198+ }
199+ }
200+
201+ /**
202+ * Receives data into an array of characters. This method will
203+ * block until some input is available.
204+ */
205+ synchronized void receive(char c[], int off, int len) throws IOException {
206+ while (--len >= 0) {
207+ receive(c[off++]);
208+ }
209+ }
210+
211+ /**
212+ * Notifies all waiting threads that the last character of data has been
213+ * received.
214+ */
215+ synchronized void receivedLast() {
216+ closedByWriter = true;
217+ notifyAll();
218+ }
219+
220+ /**
221+ * Reads the next character of data from this piped stream.
222+ * If no character is available because the end of the stream
223+ * has been reached, the value <code>-1</code> is returned.
224+ * This method blocks until input data is available, the end of
225+ * the stream is detected, or an exception is thrown.
226+ *
227+ * @return the next character of data, or <code>-1</code> if the end of the
228+ * stream is reached.
229+ * @exception IOException if the pipe is
230+ * <a href=PipedInputStream.html#BROKEN> <code>broken</code></a>,
231+ * {@link #connect(java.io.PipedWriter) unconnected}, closed,
232+ * or an I/O error occurs.
233+ */
234+ public synchronized int read() throws IOException {
235+ if (!connected) {
236+ throw new IOException("Pipe not connected");
237+ } else if (closedByReader) {
238+ throw new IOException("Pipe closed");
239+ } else if (writeSide != null && !writeSide.isAlive()
240+ && !closedByWriter && (in < 0)) {
241+ throw new IOException("Write end dead");
242+ }
243+
244+ readSide = Thread.currentThread();
245+ int trials = 2;
246+ while (in < 0) {
247+ if (closedByWriter) {
248+ /* closed by writer, return EOF */
249+ return -1;
250+ }
251+ if ((writeSide != null) && (!writeSide.isAlive()) && (--trials < 0)) {
252+ throw new IOException("Pipe broken");
253+ }
254+ /* might be a writer waiting */
255+ notifyAll();
256+ try {
257+ wait(1000);
258+ } catch (InterruptedException ex) {
259+ throw new java.io.InterruptedIOException();
260+ }
261+ }
262+ int ret = buffer[out++];
263+ if (out >= buffer.length) {
264+ out = 0;
265+ }
266+ if (in == out) {
267+ /* now empty */
268+ in = -1;
269+ }
270+ return ret;
271+ }
272+
273+ /**
274+ * Reads up to <code>len</code> characters of data from this piped
275+ * stream into an array of characters. Less than <code>len</code> characters
276+ * will be read if the end of the data stream is reached or if
277+ * <code>len</code> exceeds the pipe's buffer size. This method
278+ * blocks until at least one character of input is available.
279+ *
280+ * @param cbuf the buffer into which the data is read.
281+ * @param off the start offset of the data.
282+ * @param len the maximum number of characters read.
283+ * @return the total number of characters read into the buffer, or
284+ * <code>-1</code> if there is no more data because the end of
285+ * the stream has been reached.
286+ * @exception IOException if the pipe is
287+ * <a href=PipedInputStream.html#BROKEN> <code>broken</code></a>,
288+ * {@link #connect(java.io.PipedWriter) unconnected}, closed,
289+ * or an I/O error occurs.
290+ */
291+ public synchronized int read(char cbuf[], int off, int len) throws IOException {
292+ if (!connected) {
293+ throw new IOException("Pipe not connected");
294+ } else if (closedByReader) {
295+ throw new IOException("Pipe closed");
296+ } else if (writeSide != null && !writeSide.isAlive()
297+ && !closedByWriter && (in < 0)) {
298+ throw new IOException("Write end dead");
299+ }
300+
301+ if ((off < 0) || (off > cbuf.length) || (len < 0) ||
302+ ((off + len) > cbuf.length) || ((off + len) < 0)) {
303+ throw new IndexOutOfBoundsException();
304+ } else if (len == 0) {
305+ return 0;
306+ }
307+
308+ /* possibly wait on the first character */
309+ int c = read();
310+ if (c < 0) {
311+ return -1;
312+ }
313+ cbuf[off] = (char)c;
314+ int rlen = 1;
315+ while ((in >= 0) && (--len > 0)) {
316+ cbuf[off + rlen] = buffer[out++];
317+ rlen++;
318+ if (out >= buffer.length) {
319+ out = 0;
320+ }
321+ if (in == out) {
322+ /* now empty */
323+ in = -1;
324+ }
325+ }
326+ return rlen;
327+ }
328+
329+ /**
330+ * Tell whether this stream is ready to be read. A piped character
331+ * stream is ready if the circular buffer is not empty.
332+ *
333+ * @exception IOException if the pipe is
334+ * <a href=PipedInputStream.html#BROKEN> <code>broken</code></a>,
335+ * {@link #connect(java.io.PipedWriter) unconnected}, or closed.
336+ */
337+ public synchronized boolean ready() throws IOException {
338+ if (!connected) {
339+ throw new IOException("Pipe not connected");
340+ } else if (closedByReader) {
341+ throw new IOException("Pipe closed");
342+ } else if (writeSide != null && !writeSide.isAlive()
343+ && !closedByWriter && (in < 0)) {
344+ throw new IOException("Write end dead");
345+ }
346+ if (in < 0) {
347+ return false;
348+ } else {
349+ return true;
350+ }
351+ }
352+
353+ /**
354+ * Closes this piped stream and releases any system resources
355+ * associated with the stream.
356+ *
357+ * @exception IOException if an I/O error occurs.
358+ */
359+ public void close() throws IOException {
360+ in = -1;
361+ closedByReader = true;
362+ }
363+}