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	/*
	* Copyright (c) 1996, 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;


	/**
	* Piped character-output streams.
	*
	* @author Mark Reinhold
	* @since JDK1.1
	*/

	public class PipedWriter extends Writer {

	/* 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 PipedReader sink;

	/* This flag records the open status of this particular writer. It
	* is independent of the status flags defined in PipedReader. It is
	* used to do a sanity check on connect.
	*/
	private boolean closed = false;

	/**
	* Creates a piped writer connected to the specified piped
	* reader. Data characters written to this stream will then be
	* available as input from <code>snk</code>.
	*
	* @param snk The piped reader to connect to.
	* @exception IOException if an I/O error occurs.
	*/
	public PipedWriter(PipedReader snk) throws IOException {
	connect(snk);
	}

	/**
	* Creates a piped writer that is not yet connected to a
	* piped reader. It must be connected to a piped reader,
	* either by the receiver or the sender, before being used.
	*
	* @see java.io.PipedReader#connect(java.io.PipedWriter)
	* @see java.io.PipedWriter#connect(java.io.PipedReader)
	*/
	public PipedWriter() {
	}

	/**
	* Connects this piped writer to a receiver. If this object
	* is already connected to some other piped reader, an
	* <code>IOException</code> is thrown.
	* <p>
	* If <code>snk</code> is an unconnected piped reader and
	* <code>src</code> is an unconnected piped writer, 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 reader to connect to.
	* @exception IOException if an I/O error occurs.
	*/
	public synchronized void connect(PipedReader snk) throws IOException {
	if (snk == null) {
	throw new NullPointerException();
	} else if (sink != null \|\| snk.connected) {
	throw new IOException("Already connected");
	} else if (snk.closedByReader \|\| closed) {
	throw new IOException("Pipe closed");
	}

	sink = snk;
	snk.in = -1;
	snk.out = 0;
	snk.connected = true;
	}

	/**
	* Writes the specified <code>char</code> to the piped output stream.
	* If a thread was reading data characters from the connected piped input
	* stream, but the thread is no longer alive, then an
	* <code>IOException</code> is thrown.
	* <p>
	* Implements the <code>write</code> method of <code>Writer</code>.
	*
	* @param c the <code>char</code> to be written.
	* @exception IOException if the pipe is
	* <a href=PipedOutputStream.html#BROKEN> <code>broken</code></a>,
	* {@link #connect(java.io.PipedReader) unconnected}, closed
	* or an I/O error occurs.
	*/
	public void write(int c) throws IOException {
	if (sink == null) {
	throw new IOException("Pipe not connected");
	}
	sink.receive(c);
	}

	/**
	* Writes <code>len</code> characters from the specified character array
	* starting at offset <code>off</code> to this piped output stream.
	* This method blocks until all the characters are written to the output
	* stream.
	* If a thread was reading data characters from the connected piped input
	* stream, but the thread is no longer alive, then an
	* <code>IOException</code> is thrown.
	*
	* @param cbuf the data.
	* @param off the start offset in the data.
	* @param len the number of characters to write.
	* @exception IOException if the pipe is
	* <a href=PipedOutputStream.html#BROKEN> <code>broken</code></a>,
	* {@link #connect(java.io.PipedReader) unconnected}, closed
	* or an I/O error occurs.
	*/
	public void write(char cbuf[], int off, int len) throws IOException {
	if (sink == null) {
	throw new IOException("Pipe not connected");
	} else if ((off \| len \| (off + len) \| (cbuf.length - (off + len))) < 0) {
	throw new IndexOutOfBoundsException();
	}
	sink.receive(cbuf, off, len);
	}

	/**
	* Flushes this output stream and forces any buffered output characters
	* to be written out.
	* This will notify any readers that characters are waiting in the pipe.
	*
	* @exception IOException if the pipe is closed, or an I/O error occurs.
	*/
	public synchronized void flush() throws IOException {
	if (sink != null) {
	if (sink.closedByReader \|\| closed) {
	throw new IOException("Pipe closed");
	}
	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 characters.
	*
	* @exception IOException if an I/O error occurs.
	*/
	public void close() throws IOException {
	closed = true;
	if (sink != null) {
	sink.receivedLast();
	}
	}
	}

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