| /* |
| * Copyright (c) 1995, 2006, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.io; |
| |
| import java.io.*; |
| |
| /** |
| * A piped output stream can be connected to a piped input stream |
| * to create a communications pipe. The piped output stream is the |
| * sending end of the pipe. Typically, data is written to a |
| * <code>PipedOutputStream</code> object by one thread and data is |
| * read from the connected <code>PipedInputStream</code> by some |
| * other thread. Attempting to use both objects from a single thread |
| * is not recommended as it may deadlock the thread. |
| * The pipe is said to be <a id=BROKEN> <i>broken</i> </a> if a |
| * thread that was reading data bytes from the connected piped input |
| * stream is no longer alive. |
| * |
| * @author James Gosling |
| * @see java.io.PipedInputStream |
| * @since 1.0 |
| */ |
| public |
| class PipedOutputStream extends OutputStream { |
| |
| /* REMIND: identification of the read and write sides needs to be |
| more sophisticated. Either using thread groups (but what about |
| pipes within a thread?) or using finalization (but it may be a |
| long time until the next GC). */ |
| private PipedInputStream sink; |
| |
| /** |
| * Creates a piped output stream connected to the specified piped |
| * input stream. Data bytes written to this stream will then be |
| * available as input from <code>snk</code>. |
| * |
| * @param snk The piped input stream to connect to. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public PipedOutputStream(PipedInputStream snk) throws IOException { |
| connect(snk); |
| } |
| |
| /** |
| * Creates a piped output stream that is not yet connected to a |
| * piped input stream. It must be connected to a piped input stream, |
| * either by the receiver or the sender, before being used. |
| * |
| * @see java.io.PipedInputStream#connect(java.io.PipedOutputStream) |
| * @see java.io.PipedOutputStream#connect(java.io.PipedInputStream) |
| */ |
| public PipedOutputStream() { |
| } |
| |
| /** |
| * Connects this piped output stream to a receiver. If this object |
| * is already connected to some other piped input stream, an |
| * <code>IOException</code> is thrown. |
| * <p> |
| * If <code>snk</code> is an unconnected piped input stream and |
| * <code>src</code> is an unconnected piped output stream, they may |
| * be connected by either the call: |
| * <blockquote><pre> |
| * src.connect(snk)</pre></blockquote> |
| * or the call: |
| * <blockquote><pre> |
| * snk.connect(src)</pre></blockquote> |
| * The two calls have the same effect. |
| * |
| * @param snk the piped input stream to connect to. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public synchronized void connect(PipedInputStream snk) throws IOException { |
| if (snk == null) { |
| throw new NullPointerException(); |
| } else if (sink != null || snk.connected) { |
| throw new IOException("Already connected"); |
| } |
| sink = snk; |
| snk.in = -1; |
| snk.out = 0; |
| snk.connected = true; |
| } |
| |
| /** |
| * Writes the specified <code>byte</code> to the piped output stream. |
| * <p> |
| * Implements the <code>write</code> method of <code>OutputStream</code>. |
| * |
| * @param b the <code>byte</code> to be written. |
| * @exception IOException if the pipe is <a href=#BROKEN> broken</a>, |
| * {@link #connect(java.io.PipedInputStream) unconnected}, |
| * closed, or if an I/O error occurs. |
| */ |
| public void write(int b) throws IOException { |
| if (sink == null) { |
| throw new IOException("Pipe not connected"); |
| } |
| sink.receive(b); |
| } |
| |
| /** |
| * Writes <code>len</code> bytes from the specified byte array |
| * starting at offset <code>off</code> to this piped output stream. |
| * This method blocks until all the bytes are written to the output |
| * stream. |
| * |
| * @param b the data. |
| * @param off the start offset in the data. |
| * @param len the number of bytes to write. |
| * @exception IOException if the pipe is <a href=#BROKEN> broken</a>, |
| * {@link #connect(java.io.PipedInputStream) unconnected}, |
| * closed, or if an I/O error occurs. |
| */ |
| public void write(byte b[], int off, int len) throws IOException { |
| if (sink == null) { |
| throw new IOException("Pipe not connected"); |
| } else if (b == null) { |
| throw new NullPointerException(); |
| } else if ((off < 0) || (off > b.length) || (len < 0) || |
| ((off + len) > b.length) || ((off + len) < 0)) { |
| throw new IndexOutOfBoundsException(); |
| } else if (len == 0) { |
| return; |
| } |
| sink.receive(b, off, len); |
| } |
| |
| /** |
| * Flushes this output stream and forces any buffered output bytes |
| * to be written out. |
| * This will notify any readers that bytes are waiting in the pipe. |
| * |
| * @exception IOException if an I/O error occurs. |
| */ |
| public synchronized void flush() throws IOException { |
| if (sink != null) { |
| synchronized (sink) { |
| sink.notifyAll(); |
| } |
| } |
| } |
| |
| /** |
| * Closes this piped output stream and releases any system resources |
| * associated with this stream. This stream may no longer be used for |
| * writing bytes. |
| * |
| * @exception IOException if an I/O error occurs. |
| */ |
| public void close() throws IOException { |
| if (sink != null) { |
| sink.receivedLast(); |
| } |
| } |
| } |