diff options
Diffstat (limited to 'libjava/classpath/java/io/PipedOutputStream.java')
-rw-r--r-- | libjava/classpath/java/io/PipedOutputStream.java | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/libjava/classpath/java/io/PipedOutputStream.java b/libjava/classpath/java/io/PipedOutputStream.java new file mode 100644 index 00000000000..81881050d1b --- /dev/null +++ b/libjava/classpath/java/io/PipedOutputStream.java @@ -0,0 +1,181 @@ +/* PipedOutputStream.java -- Write portion of piped streams. + Copyright (C) 1998, 2000, 2001, 2003 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package java.io; + +// NOTE: This implementation is very similar to that of PipedWriter. If you +// fix a bug in here, chances are you should make a similar change to the +// PipedWriter code. + +/** + * This class writes its bytes to a <code>PipedInputStream</code> to + * which it is connected. + * <p> + * It is highly recommended that a <code>PipedOutputStream</code> and its + * connected <code>PipedInputStream</code> be in different threads. If + * they are in the same thread, read and write operations could deadlock + * the thread. + * + * @author Aaron M. Renn (arenn@urbanophile.com) + */ +public class PipedOutputStream extends OutputStream +{ + /** Target PipedInputStream to which this is connected. Null only if this + * OutputStream hasn't been connected yet. */ + PipedInputStream sink; + + /** Set to true if close() has been called on this OutputStream. */ + boolean closed; + + /** + * Create an unconnected PipedOutputStream. It must be connected + * to a <code>PipedInputStream</code> using the <code>connect</code> + * method prior to writing any data or an exception will be thrown. + */ + public PipedOutputStream() + { + } + + /** + * Create a new <code>PipedOutputStream</code> instance + * to write to the specified <code>PipedInputStream</code>. This stream + * is then ready for writing. + * + * @param sink The <code>PipedInputStream</code> to connect this stream to. + * + * @exception IOException If <code>sink</code> has already been connected + * to a different PipedOutputStream. + */ + public PipedOutputStream(PipedInputStream sink) throws IOException + { + sink.connect(this); + } + + /** + * Connects this object to the specified <code>PipedInputStream</code> + * object. This stream will then be ready for writing. + * + * @param sink The <code>PipedInputStream</code> to connect this stream to + * + * @exception IOException If the stream has not been connected or has + * been closed. + */ + public void connect(PipedInputStream sink) throws IOException + { + if (this.sink != null || sink.source != null) + throw new IOException ("Already connected"); + sink.connect(this); + } + + /** + * Write a single byte of date to the stream. Note that this method will + * block if the <code>PipedInputStream</code> to which this object is + * connected has a full buffer. + * + * @param b The byte of data to be written, passed as an <code>int</code>. + * + * @exception IOException If the stream has not been connected or has + * been closed. + */ + public void write(int b) throws IOException + { + if (sink == null) + throw new IOException ("Not connected"); + if (closed) + throw new IOException ("Pipe closed"); + + sink.receive (b); + } + + /** + * This method writes <code>len</code> bytes of data from the byte array + * <code>buf</code> starting at index <code>offset</code> in the array + * to the stream. Note that this method will block if the + * <code>PipedInputStream</code> to which this object is connected has + * a buffer that cannot hold all of the bytes to be written. + * + * @param buffer The array containing bytes to write to the stream. + * @param offset The index into the array to start writing bytes from. + * @param len The number of bytes to write. + * + * @exception IOException If the stream has not been connected or has + * been closed. + */ + public void write(byte[] buffer, int offset, int len) throws IOException + { + if (sink == null) + throw new IOException ("Not connected"); + if (closed) + throw new IOException ("Pipe closed"); + + sink.receive(buffer, offset, len); + } + + /** + * This method does nothing. + * + * @exception IOException If the stream is closed. + * @specnote You'd think that this method would block until the sink + * had read all available data. Thats not the case - this method + * appears to be a no-op? + */ + public void flush() throws IOException + { + } + + /** + * This method closes this stream so that no more data can be written + * to it. Any further attempts to write to this stream may throw an + * exception + * + * @exception IOException If an error occurs + */ + public void close() throws IOException + { + // A close call on an unconnected PipedOutputStream has no effect. + if (sink != null) + { + closed = true; + // Notify any waiting readers that the stream is now closed. + synchronized (sink) + { + sink.notifyAll(); + } + } + } +} |