PipedInputStream: Rewrote to be simpler and more correct.
* java/io/PipedInputStream: Rewrote to be simpler and more correct. * java/io/PipedOutputStream: Updated to match new PipedInputStream. * java/io/PipedReader: New implementation based on new PipedInputStream. * java/io/PipedWriter: Updated to match new PipedOutputStream. From-SVN: r38708
This commit is contained in:
Bryce McKinlay
Bryce McKinlay
parent
a5a4ce3c3c
commit
865b4ea73f
5 changed files with 819 additions and 1197 deletions
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@ -1,5 +1,5 @@
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/* PipedWriter.java -- Write portion of piped streams.
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Copyright (C) 1998 Free Software Foundation, Inc.
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/* PipedWriter.java -- Write portion of piped character streams.
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Copyright (C) 1998, 2000, 2001 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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@ -27,6 +27,10 @@ executable file might be covered by the GNU General Public License. */
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package java.io;
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// NOTE: This implementation is very similar to that of PipedOutputStream.
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// If you fix a bug in here, chances are you should make a similar change to
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// the PipedOutputStream code.
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/**
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* This class writes its chars to a <code>PipedReader</code> to
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* which it is connected.
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@ -36,182 +40,130 @@ package java.io;
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* they are in the same thread, read and write operations could deadlock
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* the thread.
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*
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* @version 0.0
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*
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* @author Aaron M. Renn (arenn@urbanophile.com)
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*/
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public class PipedWriter extends Writer
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{
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/** Target PipedReader to which this is connected. Null only if this
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* Writer hasn't been connected yet. */
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PipedReader sink;
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/** Set to true if close() has been called on this Writer. */
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boolean closed;
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/*************************************************************************/
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/** Buffer used to implement single-argument write */
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char[] read_buf = new char[1];
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/**
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* Create an unconnected PipedWriter. It must be connected
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* to a <code>PipedReader</code> using the <code>connect</code>
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* method prior to writing any data or an exception will be thrown.
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*/
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public PipedWriter()
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{
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}
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/*
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* Instance Variables
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*/
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/**
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* Create a new <code>PipedWriter</code> instance
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* to write to the specified <code>PipedReader</code>. This stream
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* is then ready for writing.
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*
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* @param sink The <code>PipedReader</code> to connect this stream to.
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*
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* @exception IOException If <code>sink</code> has already been connected
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* to a different PipedWriter.
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*/
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public PipedWriter(PipedReader sink) throws IOException
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{
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sink.connect(this);
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}
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/**
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* This is the <code>PipedReader</code> to which this object
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* is connected.
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*/
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private PipedReader snk;
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/**
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* Connects this object to the specified <code>PipedReader</code>
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* object. This stream will then be ready for writing.
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*
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* @param sink The <code>PipedReader</code> to connect this stream to
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*
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* @exception IOException If the stream has not been connected or has
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* been closed.
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*/
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public void connect(PipedReader sink) throws IOException
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{
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if (sink != null)
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throw new IOException ("Already connected");
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sink.connect(this);
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}
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/**
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* This flag indicates whether or not this stream has ever been
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* connected to an input stream
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*/
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private boolean ever_connected;
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/**
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* Write a single char of date to the stream. Note that this method will
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* block if the <code>PipedReader</code> to which this object is
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* connected has a full buffer.
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*
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* @param b The char of data to be written, passed as an <code>int</code>.
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*
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* @exception IOException If the stream has not been connected or has
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* been closed.
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*/
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public void write(char b) throws IOException
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{
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read_buf[0] = b;
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sink.receive (read_buf, 0, 1);
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}
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/**
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* This method writes <code>len</code> chars of data from the char array
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* <code>buf</code> starting at index <code>offset</code> in the array
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* to the stream. Note that this method will block if the
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* <code>PipedReader</code> to which this object is connected has
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* a buffer that cannot hold all of the chars to be written.
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*
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* @param buf The array containing chars to write to the stream.
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* @param offset The index into the array to start writing chars from.
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* @param len The number of chars to write.
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*
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* @exception IOException If the stream has not been connected or has
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* been closed.
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*/
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public void write(char[] b, int off, int len) throws IOException
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{
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if (sink == null)
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throw new IOException ("Not connected");
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if (closed)
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throw new IOException ("Pipe closed");
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sink.receive (b, off, len);
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}
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/**
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* This flag indicates whether the <code>close</code> method has ever
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* been called for this stream.
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*/
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private boolean closed;
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/*************************************************************************/
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/**
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* This method initializes a new <code>PipedWriter</code> instance.
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* This constructor creates an unconnected object. It must be connected
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* to a <code>PipedReader</code> object using the <code>connect</code>
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* method prior to writing any data or an exception will be thrown.
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*/
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public
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PipedWriter()
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{
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; // Do Nothing
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/**
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* This method does nothing.
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*
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* @exception IOException If the stream is closed.
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* @specnote You'd think that this method would block until the sink
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* had read all available data. Thats not the case - this method
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* appears to be a no-op?
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*/
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public void flush()
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{
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}
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/**
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* This method closes this stream so that no more data can be written
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* to it. Any further attempts to write to this stream may throw an
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* exception
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*
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* @exception IOException If an error occurs
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*/
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public void close()
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{
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// A close call on an unconnected PipedWriter has no effect.
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if (sink != null)
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{
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closed = true;
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// Notify any waiting readers that the stream is now closed.
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synchronized (sink)
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{
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sink.notifyAll();
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}
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}
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}
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}
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/*************************************************************************/
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/**
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* This method initializes a new <code>PipedWriter</code> instance
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* to write to the specified <code>PipedReader</code>. This stream
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* is then ready for writing.
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*
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* @param snk The <code>PipedReader</code> to connect this stream to.
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*
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* @exception IOException If an error occurs
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*/
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public
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PipedWriter(PipedReader snk) throws IOException
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{
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connect(snk);
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}
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/*************************************************************************/
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/*
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* Instance Methods
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*/
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/**
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* This method connects this object to the specified
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* <code>PipedReader</code> object. This stream will then be ready
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* for writing. If this stream is already connected or has been
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* previously closed, then an exception is thrown.
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*
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* @param snk The <code>PipedReader</code> to connect this stream to
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*
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* @exception IOException If an error occurs
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*/
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public void
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connect(PipedReader snk) throws IOException
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{
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if (snk == this.snk)
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return;
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if (ever_connected)
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throw new IOException("Already connected");
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if (closed)
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throw new IOException("Stream is closed and cannot be reopened");
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synchronized (lock) {
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this.snk = snk;
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ever_connected = true;
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snk.src = this;
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snk.connect(this);
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} // synchronized
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}
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/*************************************************************************/
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/**
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* This method closes this stream so that no more data can be written
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* to it. Any further attempts to write to this stream may throw an
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* exception
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*
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* @exception IOException If an error occurs
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*/
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public void
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close() throws IOException
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{
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synchronized (lock) {
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closed = true;
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snk.close();
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notifyAll();
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} // synchronized
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}
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/*************************************************************************/
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/**
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* This methods writes a single byte of data to the pipe. This call may
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* block if the pipe is full.
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*
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* @param c The <code>char</code> to write, passed as an <code>int</code>.
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*
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* @exception IOException If an error occurs.
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*/
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public void
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write(int c) throws IOException
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{
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char[] buf = new char[1];
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buf[0] = (char)c;
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write(buf, 0, buf.length);
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}
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/*************************************************************************/
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/**
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* This method writes <code>len</code> chars of data from the char array
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* <code>buf</code> starting at index <code>offset</code> in the array
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* to the stream. Note that this method will block if the
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* <code>PipedReader</code> to which this object is connected has
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* a buffer that cannot hold all of the chars to be written.
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*
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* @param buf The array containing chars to write to thes stream.
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* @param offset The index into the array to start writing chars from.
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* @param len The number of chars to write.
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*
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* @exception IOException If an error occurs
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*/
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public void
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write(char[] buf, int offset, int len) throws IOException
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{
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snk.write(buf, 0, len);
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}
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/*************************************************************************/
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/**
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* This method flushes any unwritten chars to the underlying output
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* sink. This method does nothing in this class because this class does
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* not buffer any chars.
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*
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* @exception IOException If an error occurs
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*/
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public void
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flush() throws IOException
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{
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; // Do Nothing
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}
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} // class PipedWriter
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