| /* PipedWriter.java -- Write portion of piped character 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 PipedOutputStream. |
| // If you fix a bug in here, chances are you should make a similar change to |
| // the PipedOutputStream code. |
| |
| /** |
| * This class writes its chars to a <code>PipedReader</code> to |
| * which it is connected. |
| * <p> |
| * It is highly recommended that a <code>PipedWriter</code> and its |
| * connected <code>PipedReader</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 PipedWriter extends Writer |
| { |
| /** Target PipedReader to which this is connected. Null only if this |
| * Writer hasn't been connected yet. */ |
| PipedReader sink; |
| |
| /** Set to true if close() has been called on this Writer. */ |
| boolean closed; |
| |
| /** Buffer used to implement single-argument write */ |
| char[] read_buf = new char[1]; |
| |
| /** |
| * Create an unconnected PipedWriter. It must be connected |
| * to a <code>PipedReader</code> using the <code>connect</code> |
| * method prior to writing any data or an exception will be thrown. |
| */ |
| public PipedWriter() |
| { |
| } |
| |
| /** |
| * Create a new <code>PipedWriter</code> instance |
| * to write to the specified <code>PipedReader</code>. This stream |
| * is then ready for writing. |
| * |
| * @param sink The <code>PipedReader</code> to connect this stream to. |
| * |
| * @exception IOException If <code>sink</code> has already been connected |
| * to a different PipedWriter. |
| */ |
| public PipedWriter(PipedReader sink) throws IOException |
| { |
| sink.connect(this); |
| } |
| |
| /** |
| * Connects this object to the specified <code>PipedReader</code> |
| * object. This stream will then be ready for writing. |
| * |
| * @param sink The <code>PipedReader</code> to connect this stream to |
| * |
| * @exception IOException If the stream has not been connected or has |
| * been closed. |
| */ |
| public void connect(PipedReader sink) throws IOException |
| { |
| if (this.sink != null || sink.source != null) |
| throw new IOException ("Already connected"); |
| sink.connect(this); |
| } |
| |
| /** |
| * Write a single char of date to the stream. Note that this method will |
| * block if the <code>PipedReader</code> to which this object is |
| * connected has a full buffer. |
| * |
| * @param b The char 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 |
| { |
| read_buf[0] = (char) (b & 0xffff); |
| sink.receive (read_buf, 0, 1); |
| } |
| |
| /** |
| * This method writes <code>len</code> chars of data from the char 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>PipedReader</code> to which this object is connected has |
| * a buffer that cannot hold all of the chars to be written. |
| * |
| * @param buffer The array containing chars to write to the stream. |
| * @param offset The index into the array to start writing chars from. |
| * @param len The number of chars to write. |
| * |
| * @exception IOException If the stream has not been connected or has |
| * been closed. |
| */ |
| public void write(char[] 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 |
| { |
| if (closed) |
| throw new IOException ("Pipe closed"); |
| } |
| |
| /** |
| * 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 PipedWriter has no effect. |
| if (sink != null) |
| { |
| closed = true; |
| // Notify any waiting readers that the stream is now closed. |
| synchronized (sink) |
| { |
| sink.notifyAll(); |
| } |
| } |
| } |
| } |