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Diffstat (limited to 'libjava/java/io/PipedOutputStream.java')
| -rw-r--r-- | libjava/java/io/PipedOutputStream.java | 280 |
1 files changed, 196 insertions, 84 deletions
diff --git a/libjava/java/io/PipedOutputStream.java b/libjava/java/io/PipedOutputStream.java index 901fb9e..6d10612 100644 --- a/libjava/java/io/PipedOutputStream.java +++ b/libjava/java/io/PipedOutputStream.java @@ -1,97 +1,209 @@ -// PipedOutputStream.java - Write bytes to a pipe. +/* PipedOutputStream.java -- Write portion of piped streams. + Copyright (C) 1998 Free Software Foundation, Inc. -/* Copyright (C) 1998, 1999, 2000 Free Software Foundation +This file is part of GNU Classpath. - This file is part of libgcj. +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., 59 Temple Place, Suite 330, Boston, MA +02111-1307 USA. + +As a special exception, if you link this library with other files to +produce an executable, this library does not by itself cause the +resulting executable to be covered by the GNU General Public License. +This exception does not however invalidate any other reasons why the +executable file might be covered by the GNU General Public License. */ -This software is copyrighted work licensed under the terms of the -Libgcj License. Please consult the file "LIBGCJ_LICENSE" for -details. */ package java.io; /** - * @author Tom Tromey <tromey@cygnus.com> - * @date September 24, 1998 + * 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. + * + * @version 0.0 + * + * @author Aaron M. Renn (arenn@urbanophile.com) + */ +public class PipedOutputStream extends OutputStream +{ + +/*************************************************************************/ + +/* + * Instance Variables */ -/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3 - * "The Java Language Specification", ISBN 0-201-63451-1 - * Status: Believed complete and correct. +/** + * This is the <code>PipedInputStream</code> to which this object + * is connected. + */ +private PipedInputStream snk; + +/** + * This flag indicates whether or not this stream has ever been + * connected to an input stream + */ +private boolean ever_connected; + +/** + * This flag indicates whether the <code>close</code> method has ever + * been called for this stream. + */ +private boolean closed; + +/*************************************************************************/ + +/** + * This method initializes a new <code>PipedOutputStream</code> instance. + * This constructor creates an unconnected object. It must be connected + * to a <code>PipedInputStream</code> object using the <code>connect</code> + * method prior to writing any data or an exception will be thrown. + */ +public +PipedOutputStream() +{ + ; // Do Nothing +} + +/*************************************************************************/ + +/** + * This method initializes a new <code>PipedOutputStream</code> instance + * to write to the specified <code>PipedInputStream</code>. This stream + * is then ready for writing. + * + * @param snk The <code>PipedInputStream</code> to connect this stream to. + * + * @exception IOException If an error occurs + */ +public +PipedOutputStream(PipedInputStream snk) throws IOException +{ + connect(snk); +} + +/*************************************************************************/ + +/* + * Instance Methods */ -public class PipedOutputStream extends OutputStream +/** + * This method connects this object to the specified + * <code>PipedInputStream</code> object. This stream will then be ready + * for writing. If this stream is already connected or has been + * previously closed, then an exception is thrown. + * + * @param snk The <code>PipedInputStream</code> to connect this stream to + * + * @exception IOException If an error occurs + */ +public synchronized void +connect(PipedInputStream snk) throws IOException { - public void close () throws IOException - { - closed = true; - - // Notify PipedInputStream that there is no more data to be had. - destination.receive(-1); - } - - public void connect (PipedInputStream dest) throws IOException - { - if (closed) - throw new IOException("pipe closed"); - - if (destination != null) - if (destination == dest) - return; - else - throw new IOException("pipe already connected"); - - destination = dest; - try - { - dest.connect(this); - } - catch (IOException ex) - { - destination = null; - throw ex; - } - } - - public synchronized void flush () throws IOException - { - // There doesn't seem to be anything to do here. - - // TBD: Should this maybe do a notifyAll as a way for the user - // to wake up the input stream to check for bytes to read? Shouldn't - // be necessary but if there aren't any bytes, other threads will just - // go blocak again anyway so it wouldn't hurt. - } - - public PipedOutputStream () - { - closed = false; - } - - public PipedOutputStream (PipedInputStream dest) throws IOException - { - closed = false; - connect (dest); - } - - public void write (int oneByte) throws IOException - { - if (closed) - throw new IOException (); - destination.receive(oneByte); - } - - public void write (byte[] buffer, int offset, int count) throws IOException - { - if (closed) - throw new IOException (); - if (offset < 0 || count < 0 || offset + count > buffer.length) - throw new ArrayIndexOutOfBoundsException (); - for (int i = 0; i < count; ++i) - destination.receive (buffer[offset + i]); - } - - // Instance variables. - private PipedInputStream destination; - private boolean closed; + if (snk == this.snk) + return; + + if (ever_connected) + throw new IOException("Already connected"); + + if (closed) + throw new IOException("Stream is closed and cannot be reopened"); + + this.snk = snk; + ever_connected = true; + snk.src = this; + + snk.connect(this); +} + +/*************************************************************************/ + +/** + * 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 synchronized void +close() throws IOException +{ + closed = true; + snk.close(); + notifyAll(); +} + +/*************************************************************************/ + +/** + * This method writes 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 an error occurs + */ +public synchronized void +write(int b) throws IOException +{ + byte[] buf = new byte[1]; + buf[0] = (byte)(b & 0xFF); + + snk.write(buf, 0, buf.length); } + +/*************************************************************************/ + +/** + * 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 buf The array containing bytes to write to thes stream. + * @param offset The index into the array to start writing bytes from. + * @param len The number of bytes to write. + * + * @exception IOException If an error occurs + */ +public void +write(byte[] buf, int offset, int len) throws IOException +{ + snk.write(buf, 0, len); +} + +/*************************************************************************/ + +/** + * This method flushes any unwritten bytes to the output and notifies + * any waiting readers that the pipe is ready to be read. + * + * @exception IOException If an error occurs. + */ +public void +flush() throws IOException +{ + return; +} + +} // class PipedOutputStream + |