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Commit 865b4ea7 by Bryce McKinlay Committed by Bryce McKinlay
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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
parent a5a4ce3c
Showing with 621 additions and 999 deletions
libjava/ChangeLog
...@@ -2,6 +2,12 @@ ...@@ -2,6 +2,12 @@
* java/lang/Thread.java: Update comment. * java/lang/Thread.java: Update comment.
* 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.
2001-01-03 Tom Tromey <tromey@redhat.com> 2001-01-03 Tom Tromey <tromey@redhat.com>
* java/awt/ScrollPane.java (setBlockIncrement): Throw error. * java/awt/ScrollPane.java (setBlockIncrement): Throw error.
......
libjava/java/io/PipedInputStream.java
/* PipedInputStream.java -- Input stream that reads from an output stream /* PipedInputStream.java -- Read portion of piped streams.
Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc. Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
This file is part of GNU Classpath. This file is part of GNU Classpath.
...@@ -24,467 +24,334 @@ resulting executable to be covered by the GNU General Public License. ...@@ -24,467 +24,334 @@ resulting executable to be covered by the GNU General Public License.
This exception does not however invalidate any other reasons why the This exception does not however invalidate any other reasons why the
executable file might be covered by the GNU General Public License. */ executable file might be covered by the GNU General Public License. */
// NOTE: This implementation is very similar to that of PipedReader. If you
// fix a bug in here, chances are you should make a similar change to the
// PipedReader code.
package java.io; package java.io;
/** /**
* This class is an input stream that reads its bytes from an output stream * An input stream that reads its bytes from an output stream
* to which it is connected. * to which it is connected.
* <p> * <p>
* Data is read and written to an internal buffer. It is highly recommended * Data is read and written to an internal buffer. It is highly recommended
* that the <code>PipedInputStream</code> and connected <code>PipedOutputStream</code> * that the <code>PipedInputStream</code> and connected <code>PipedOutputStream</code>
* be part of different threads. If they are not, there is a possibility * be part of different threads. If they are not, the read and write
* that the read and write operations could deadlock their thread. * operations could deadlock their thread.
* *
* @version 0.0 * @specnote The JDK implementation appears to have some undocumented
* functionality where it keeps track of what thread is writing
* to pipe and throws an IOException if that thread susequently
* dies. This behaviour seems dubious and unreliable - we don't
* implement it.
* *
* @author Aaron M. Renn (arenn@urbanophile.com) * @author Aaron M. Renn (arenn@urbanophile.com)
*/ */
public class PipedInputStream extends InputStream public class PipedInputStream extends InputStream
{ {
/** PipedOutputStream to which this is connected. Null only if this
* InputStream hasn't been connected yet. */
PipedOutputStream source;
/*************************************************************************/ /** Set to true if close() has been called on this InputStream. */
boolean closed;
/* /**
* Class Variables * The size of the internal buffer used for input/output.
*/ */
protected static final int PIPE_SIZE = 2048;
/** /**
* The size of the internal buffer used for input/output. Note that this
* can be overriden by setting the system property
* <code>gnu.java.io.PipedInputStream.pipe_size</code> to the desired size shown
* in bytes. This is not a standard part of the class library. Note that
* since this variable is <code>final</code>, it cannot be changed to refect
* the size specified in the property.
* <p>
* The value for this variable is 2048.
*/
protected static final int PIPE_SIZE = 2048;
/**
* This is the real pipe size. It defaults to PIPE_SIZE, unless overridden
* by use of the system property <code>gnu.java.io.PipedInputStream.pipe_size</code>.
*/
private static int pipe_size;
static
{
pipe_size = Integer.getInteger("gnu.java.io.PipedInputStream.pipe_size",
PIPE_SIZE).intValue();
}
/*************************************************************************/
/*
* Instance Variables
*/
/**
* This is the internal circular buffer used for storing bytes written * This is the internal circular buffer used for storing bytes written
* to the pipe and from which bytes are read by this stream * to the pipe and from which bytes are read by this stream
*/ */
protected byte[] buffer = new byte[pipe_size]; protected byte[] buffer = new byte[PIPE_SIZE];
/** /**
* The index into buffer where the bytes written byte the connected * The index into buffer where the next byte from the connected
* <code>PipedOutputStream</code> will be written. If this variables is less * <code>PipedOutputStream</code> will be written. If this variable is
* than 0, then the buffer is empty. If this variable is equal to * equal to <code>out</code>, then the buffer is full. If set to < 0,
* <code>out</code>, then the buffer is full * the buffer is empty.
*/ */
protected int in = -1; protected int in = -1;
/** /**
* This index into the buffer where bytes will be read from. * This index into the buffer where bytes will be read from.
*/ */
protected int out = 0; protected int out = 0;
/**
* This variable is <code>true</code> if this object has ever been connected
* to a <code>PipedOutputStream</code>, and <code>false</code> otherwise. It is used
* to detect an attempt to connect an already connected stream or to
* otherwise use the stream before it is connected.
*/
private boolean ever_connected = false;
/**
* This variable is set to <code>true</code> if the <code>close()</code> method is
* called. This value is checked prevents a caller from re-opening the
* stream.
*/
private boolean closed = false;
/**
* This variable is the PipedOutputStream to which this stream is connected.
*/
PipedOutputStream src;
/**
* Used by <code>read()</code> to call an overloaded method
*/
private byte[] read_buf = new byte[1];
/*************************************************************************/
/* /** Buffer used to implement single-argument read/receive */
* Constructors private byte[] read_buf = new byte[1];
*/
/** /**
* This constructor creates a new <code>PipedInputStream</code> that is not * Creates a new <code>PipedInputStream</code> that is not connected to a
* connected to a <code>PipedOutputStream</code>. It must be connected before * <code>PipedOutputStream</code>. It must be connected before bytes can
* bytes can be read from this stream. * be read from this stream.
*/ */
public public PipedInputStream()
PipedInputStream() {
{ }
return;
}
/*************************************************************************/
/** /**
* This constructor creates a new <code>PipedInputStream</code> and connects * This constructor creates a new <code>PipedInputStream</code> and connects
* it to the passed in <code>PipedOutputStream</code>. The stream is then read * it to the passed in <code>PipedOutputStream</code>. The stream is then
* for reading. * ready for reading.
* *
* @param src The <code>PipedOutputStream</code> to connect this stream to * @param source The <code>PipedOutputStream</code> to connect this stream to
* *
* @exception IOException If an error occurs * @exception IOException If <code>source</code> is already connected.
*/
public
PipedInputStream(PipedOutputStream src) throws IOException
{
connect(src);
}
/*************************************************************************/
/*
* Instance Variables
*/ */
public PipedInputStream(PipedOutputStream source) throws IOException
{
connect(source);
}
/** /**
* This method connects this stream to the passed in <code>PipedOutputStream</code>. * This method connects this stream to the passed in <code>PipedOutputStream</code>.
* This stream is then ready for reading. If this stream is already * This stream is then ready for reading. If this stream is already
* connected or has been previously closed, then an exception is thrown * connected or has been previously closed, then an exception is thrown
* *
* @param src The <code>PipedOutputStream</code> to connect this stream to * @param src The <code>PipedOutputStream</code> to connect this stream to
* *
* @exception IOException If an error occurs * @exception IOException If this PipedInputStream or <code>source</code>
* has been connected already.
*/ */
public synchronized void public void connect(PipedOutputStream source) throws IOException
connect(PipedOutputStream src) throws IOException {
{ // The JDK (1.3) does not appear to check for a previously closed
if (src == this.src) // connection here.
return;
if (ever_connected)
throw new IOException("Already connected");
if (closed)
throw new IOException("Stream is closed and cannot be reopened");
src.connect(this);
ever_connected = true; if (this.source != null || source.sink != null)
} throw new IOException ("Already connected");
/*************************************************************************/ source.sink = this;
this.source = source;
}
/** /**
* This methods closes the stream so that no more data can be read * This method receives a byte of input from the source PipedOutputStream.
* from it. * If the internal circular buffer is full, this method blocks.
* *
* @exception IOException If an error occurs * @param byte_received The byte to write to this stream
*
* @exception IOException if error occurs
* @specnote Weird. This method must be some sort of accident.
*/ */
public synchronized void protected synchronized void receive(int b) throws IOException
close() throws IOException {
{ read_buf[0] = (byte) (b & 0xff);
closed = true; receive (read_buf, 0, 1);
notifyAll(); }
}
/*************************************************************************/
/** /**
* This method returns the number of bytes that can be read from this stream * This method is used by the connected <code>PipedOutputStream</code> to
* before blocking could occur. This is the number of bytes that are * write bytes into the buffer.
* currently unread in the internal circular buffer. Note that once this
* many additional bytes are read, the stream may block on a subsequent
* read, but it not guaranteed to block.
* *
* @return The number of bytes that can be read before blocking might occur * @param buf The array containing bytes to write to this stream
* @param offset The offset into the array to start writing from
* @param len The number of bytes to write.
* *
* @exception IOException If an error occurs * @exception IOException If an error occurs
* @specnote This code should be in PipedOutputStream.write, but we
* put it here in order to support that bizarre recieve(int)
* method.
*/ */
public synchronized int synchronized void receive(byte[] buf, int offset, int len)
available() throws IOException throws IOException
{ {
if (in == -1) if (closed)
return(0); throw new IOException ("Pipe closed");
else if (in > out)
return(in - out);
else
return(in + (pipe_size - out));
}
/*************************************************************************/ int bufpos = offset;
int copylen;
/** while (len > 0)
* Reads the next byte from the stream. The byte read is returned as {
* and int in the range of 0-255. If a byte cannot be read because of an try
* end of stream condition, -1 is returned. If the stream is already {
* closed, an IOException will be thrown. while (in == out)
* <code> {
// The pipe is full. Wake up any readers and wait for them.
notifyAll();
wait();
// The pipe could have been closed while we were waiting.
if (closed)
throw new IOException ("Pipe closed");
}
}
catch (InterruptedException ix)
{
throw new InterruptedIOException ();
}
if (in < 0) // The pipe is empty.
in = 0;
// Figure out how many bytes from buf can be copied without
// overrunning out or going past the length of the buffer.
if (in < out)
copylen = Math.min (len, out - in);
else
copylen = Math.min (len, buffer.length - in);
// Copy bytes until the pipe is filled, wrapping if neccessary.
System.arraycopy(buf, bufpos, buffer, in, copylen);
len -= copylen;
bufpos += copylen;
in += copylen;
if (in == buffer.length)
in = 0;
}
// Notify readers that new data is in the pipe.
notifyAll();
}
/**
* This method reads bytes from the stream into a caller supplied buffer.
* It starts storing bytes at position <code>offset</code> into the buffer and
* reads a maximum of <cod>>len</code> bytes. Note that this method can actually
* read fewer than <code>len</code> bytes. The actual number of bytes read is
* returned. A -1 is returned to indicated that no bytes can be read
* because the end of the stream was reached. If the stream is already
* closed, a -1 will again be returned to indicate the end of the stream.
* <p>
* This method will block if no bytes are available to be read. * This method will block if no bytes are available to be read.
* *
* @return The byte read or -1 if end of stream. * @param buf The buffer into which bytes will be stored
* * @param offset The index into the buffer at which to start writing.
* @exception IOException If an error occurs * @param len The maximum number of bytes to read.
*/ */
public synchronized int public int read() throws IOException
read() throws IOException {
{
// Method operates by calling the multibyte overloaded read method // Method operates by calling the multibyte overloaded read method
// Note that read_buf is an internal instance variable. I allocate it // Note that read_buf is an internal instance variable. I allocate it
// there to avoid constant reallocation overhead for applications that // there to avoid constant reallocation overhead for applications that
// call this method in a loop at the cost of some unneeded overhead // call this method in a loop at the cost of some unneeded overhead
// if this method is never called. // if this method is never called.
int bytes_read = read(read_buf, 0, read_buf.length); int r = read(read_buf, 0, 1);
if (bytes_read == -1) if (r == -1)
return(-1); return -1;
else else
return((read_buf[0] & 0xFF)); return read_buf[0];
} }
/*************************************************************************/
/** /**
* This method reads bytes from the stream into a caller supplied buffer. * This method reads bytes from the stream into a caller supplied buffer.
* It starts storing bytes at position <code>offset</code> into the buffer and * It starts storing bytes at position <code>offset</code> into the buffer and
* reads a maximum of <cod>>len</code> bytes. Note that this method can actually * reads a maximum of <cod>>len</code> bytes. Note that this method can actually
* read fewer than <code>len</code> bytes. The actual number of bytes read is * read fewer than <code>len</code> bytes. The actual number of bytes read is
* returned. A -1 is returned to indicated that no bytes can be read * returned. A -1 is returned to indicated that no bytes can be read
* because the end of the stream was reached. If the stream is already * because the end of the stream was reached - ie close() was called on the
* closed, a -1 will again be returned to indicate the end of the stream. * connected PipedOutputStream.
* <p> * <p>
* This method will block if no bytes are available to be read. * This method will block if no bytes are available to be read.
* *
* @param buf The buffer into which bytes will be stored * @param buf The buffer into which bytes will be stored
* @param offset The index into the buffer at which to start writing. * @param offset The index into the buffer at which to start writing.
* @param len The maximum number of bytes to read. * @param len The maximum number of bytes to read.
*
* @exception IOException If <code>close()/code> was called on this Piped
* InputStream.
*/ */
public synchronized int public synchronized int read(byte[] buf, int offset, int len)
read(byte[] buf, int offset, int len) throws IOException throws IOException
{
if (!ever_connected)
throw new IOException("Not connected");
int bytes_read = 0;
for (;;)
{
// If there are bytes, take them.
if (in != -1)
{ {
int desired_bytes = len - bytes_read; if (source == null)
throw new IOException ("Not connected");
if (closed)
throw new IOException ("Pipe closed");
// We are in a "wrap" condition. // If the buffer is empty, wait until there is something in the pipe
if (out >= in) // to read.
try
{ {
desired_bytes = Math.min (desired_bytes, pipe_size - out); while (in < 0)
System.arraycopy (buffer, out, buf, offset + bytes_read,
desired_bytes);
bytes_read += desired_bytes;
out += desired_bytes;
desired_bytes = len - bytes_read;
if (out == pipe_size)
{ {
out = 0; if (source.closed)
// OUT has wrapped. Make sure that we don't falsely return -1;
// indicate that the buffer is full. wait();
if (in == 0)
in = -1;
} }
notifyAll();
} }
catch (InterruptedException ix)
{
throw new InterruptedIOException();
}
int total = 0;
int copylen;
// We are in a "no wrap". This can be triggered by while (true)
// fall-through from the above.
if (in > out)
{ {
desired_bytes = Math.min (desired_bytes, in - out); // Figure out how many bytes from the pipe can be copied without
// overrunning in or going past the length of buf.
if (out < in)
copylen = Math.min (len, in - out);
else
copylen = Math.min (len, buffer.length - out);
System.arraycopy(buffer, out, buf, offset + bytes_read, System.arraycopy (buffer, out, buf, offset, copylen);
desired_bytes); offset += copylen;
len -= copylen;
out += copylen;
total += copylen;
bytes_read += desired_bytes; if (out == buffer.length)
out += desired_bytes; out = 0;
desired_bytes = len - bytes_read;
if (out == in) if (out == in)
{ {
// Don't falsely indicate that the buffer is full. // Pipe is now empty.
out = 0;
in = -1; in = -1;
}
else if (out == pipe_size)
out = 0; out = 0;
notifyAll();
} }
}
// Return when we've read something. A short return is ok.
// Also return in the case where LEN==0.
if (bytes_read > 0 || bytes_read == len)
return(bytes_read);
// Handle the case where the end of stream was encountered. // If output buffer is filled or the pipe is empty, we're done.
if (closed) if (len == 0 || in == -1)
{
if (in == -1)
{ {
// The stream is closed and empty. We've already // Notify any waiting outputstream that there is now space
// returned if bytes were read. So we know EOF is the // to write.
// only answer. notifyAll();
return -1; return total;
}
// I think this shouldn't happen. I don't think there is a
// way to get here when nothing has been read but there are
// bytes in the buffer. Still...
continue;
} }
// Wait for a byte to be received.
try
{
wait();
} }
catch(InterruptedException e) { ; }
} }
}
/*************************************************************************/
/** /**
* This method receives a byte of input from the source PipedOutputStream. * This method returns the number of bytes that can be read from this stream
* If there is no data ready to be written, or if the internal circular * before blocking could occur. This is the number of bytes that are
* buffer is full, this method blocks. * currently unread in the internal circular buffer. Note that once this
* * many additional bytes are read, the stream may block on a subsequent
* @param byte_received The byte to write to this stream * read, but it not guaranteed to block.
*
* @exception IOException if error occurs
*
*/
protected synchronized void
receive(int byte_received) throws IOException
{
// This is really slow, but it has the benefit of not duplicating
// the complicated machinery in receive(byte[],int,int).
byte[] buf = new byte[1];
buf[0] = (byte) (byte_received & 0xff);
receive (buf, 0, 1);
}
/*************************************************************************/
/**
* This method is used by the connected <code>PipedOutputStream</code> to
* write bytes into the buffer. It uses this method instead of directly
* writing the bytes in order to obtain ownership of the object's monitor
* for the purposes of calling <code>notify</code>.
* *
* @param buf The array containing bytes to write to this stream * @return The number of bytes that can be read before blocking might occur
* @param offset The offset into the array to start writing from
* @param len The number of bytes to write.
* *
* @exception IOException If an error occurs * @exception IOException If an error occurs
*/ */
synchronized void public synchronized int available() throws IOException
receive(byte[] buf, int offset, int len) throws IOException
{
if (len <= 0)
return;
int total_written = 0;
outer:
while (total_written < len)
{
// If the buffer is full, then wait.
// Also, if we are at the end of the buffer and OUT is 0, wait.
if (! (in == out
|| (in == pipe_size - 1 && out == 0)))
{
// This is the "no wrap" situation
if (in > out)
{ {
int bytes_written = 0; // The JDK 1.3 implementation does not appear to check for the closed or
if ((pipe_size - in) > (len - total_written)) // unconnected stream conditions here.
bytes_written = (len - total_written);
else if (out == 0)
bytes_written = (pipe_size - in) - 1;
else
bytes_written = (pipe_size - in);
if (bytes_written > 0)
{
System.arraycopy(buf, offset + total_written, buffer, in,
bytes_written);
total_written += bytes_written;
in += bytes_written;
if (in == pipe_size) if (in < 0)
in = 0; return 0;
else if (out < in)
notifyAll(); return in - out;
}
}
// This is the "wrap" situtation
if ((out > in) && (total_written != len))
{
int bytes_written = 0;
// Do special processing if we are at the beginning
if (in == -1)
{
in = 0;
bytes_written = Math.min (len - total_written, pipe_size);
}
else else
{ return (buffer.length - out) + in;
bytes_written = Math.min (len - total_written,
out - in);
} }
System.arraycopy(buf, offset + total_written, buffer, in, /**
bytes_written); * This methods closes the stream so that no more data can be read
total_written += bytes_written; * from it.
in += bytes_written; *
* @exception IOException If an error occurs
if (in == pipe_size) */
in = 0; public synchronized void close() throws IOException
notifyAll();
}
}
// Wait for some reads to occur before we write anything.
else
{
try
{ {
wait(); closed = true;
} // Wake any thread which may be in receive() waiting to write data.
catch (InterruptedException e) { ; } notifyAll();
}
} }
} }
} // class PipedInputStream
libjava/java/io/PipedOutputStream.java
/* PipedOutputStream.java -- Write portion of piped streams. /* PipedOutputStream.java -- Write portion of piped streams.
Copyright (C) 1998, 2000 Free Software Foundation, Inc. Copyright (C) 1998, 2000, 2001 Free Software Foundation, Inc.
This file is part of GNU Classpath. This file is part of GNU Classpath.
...@@ -27,6 +27,10 @@ executable file might be covered by the GNU General Public License. */ ...@@ -27,6 +27,10 @@ executable file might be covered by the GNU General Public License. */
package java.io; package java.io;
// NOTE: This implementation is very similar to that of PipedWriter. If you
// fix a bug in here, chances are you should make a similar change to the
// PipedWriter code.
/** /**
* This class writes its bytes to a <code>PipedInputStream</code> to * This class writes its bytes to a <code>PipedInputStream</code> to
* which it is connected. * which it is connected.
...@@ -36,171 +40,131 @@ package java.io; ...@@ -36,171 +40,131 @@ package java.io;
* they are in the same thread, read and write operations could deadlock * they are in the same thread, read and write operations could deadlock
* the thread. * the thread.
* *
* @version 0.0
*
* @author Aaron M. Renn (arenn@urbanophile.com) * @author Aaron M. Renn (arenn@urbanophile.com)
*/ */
public class PipedOutputStream extends OutputStream public class PipedOutputStream extends OutputStream
{ {
/** Target PipedInputStream to which this is connected. Null only if this
* OutputStream hasn't been connected yet. */
PipedInputStream sink;
/*************************************************************************/ /** Set to true if close() has been called on this OutputStream. */
boolean closed;
/*
* Instance Variables
*/
/**
* 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. * Create an unconnected PipedOutputStream. It must be connected
* This constructor creates an unconnected object. It must be connected * to a <code>PipedInputStream</code> using the <code>connect</code>
* to a <code>PipedInputStream</code> object using the <code>connect</code>
* method prior to writing any data or an exception will be thrown. * method prior to writing any data or an exception will be thrown.
*/ */
public public PipedOutputStream()
PipedOutputStream() {
{ }
; // Do Nothing
}
/*************************************************************************/
/** /**
* This method initializes a new <code>PipedOutputStream</code> instance * Create a new <code>PipedOutputStream</code> instance
* to write to the specified <code>PipedInputStream</code>. This stream * to write to the specified <code>PipedInputStream</code>. This stream
* is then ready for writing. * is then ready for writing.
* *
* @param snk The <code>PipedInputStream</code> to connect this stream to. * @param sink The <code>PipedInputStream</code> to connect this stream to.
* *
* @exception IOException If an error occurs * @exception IOException If <code>sink</code> has already been connected
* to a different PipedOutputStream.
*/ */
public public PipedOutputStream(PipedInputStream sink) throws IOException
PipedOutputStream(PipedInputStream snk) throws IOException {
{ sink.connect(this);
connect(snk); }
}
/**
/*************************************************************************/ * Connects this object to the specified <code>PipedInputStream</code>
* object. This stream will then be ready for writing.
/*
* Instance Methods
*/
/**
* 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 * @param sink The <code>PipedInputStream</code> to connect this stream to
* *
* @exception IOException If an error occurs * @exception IOException If the stream has not been connected or has
* been closed.
*/ */
public synchronized void public void connect(PipedInputStream sink) throws IOException
connect(PipedInputStream snk) throws IOException {
{ if (sink != null)
if (snk == this.snk) throw new IOException ("Already connected");
return; sink.connect(this);
}
if (ever_connected)
throw new IOException("Already connected"); /**
* Write a single byte of date to the stream. Note that this method will
if (closed) * block if the <code>PipedInputStream</code> to which this object is
throw new IOException("Stream is closed and cannot be reopened"); * connected has a full buffer.
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>. * @param b The byte of data to be written, passed as an <code>int</code>.
* *
* @exception IOException If an error occurs * @exception IOException If the stream has not been connected or has
* been closed.
*/ */
public synchronized void public void write(int b) throws IOException
write(int b) throws IOException {
{ if (sink == null)
snk.receive (b); throw new IOException ("Not connected");
} if (closed)
throw new IOException ("Pipe closed");
/*************************************************************************/ sink.receive (b);
}
/** /**
* This method writes <code>len</code> bytes of data from the byte array * 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 * <code>buf</code> starting at index <code>offset</code> in the array
* to the stream. Note that this method will block if the * to the stream. Note that this method will block if the
* <code>PipedInputStream</code> to which this object is connected has * <code>PipedInputStream</code> to which this object is connected has
* a buffer that cannot hold all of the bytes to be written. * a buffer that cannot hold all of the bytes to be written.
* *
* @param buf The array containing bytes to write to thes stream. * @param buf The array containing bytes to write to the stream.
* @param offset The index into the array to start writing bytes from. * @param offset The index into the array to start writing bytes from.
* @param len The number of bytes to write. * @param len The number of bytes to write.
* *
* @exception IOException If an error occurs * @exception IOException If the stream has not been connected or has
* been closed.
*/ */
public void public void write(byte[] b, int off, int len) throws IOException
write(byte[] buf, int offset, int len) throws IOException {
{ if (sink == null)
snk.receive (buf, 0, len); throw new IOException ("Not connected");
} if (closed)
throw new IOException ("Pipe closed");
/*************************************************************************/ sink.receive (b, off, len);
}
/** /**
* This method flushes any unwritten bytes to the output and notifies * This method does nothing.
* any waiting readers that the pipe is ready to be read.
* *
* @exception IOException If an error occurs. * @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 public void flush()
flush() throws IOException {
{ }
return;
}
} // class PipedOutputStream
/**
* 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()
{
// A close call on an unconnected PipedOutputStream has no effect.
if (sink != null)
{
closed = true;
// Notify any waiting readers that the stream is now closed.
synchronized (sink)
{
sink.notifyAll();
}
}
}
}
libjava/java/io/PipedReader.java
/* PipedReader.java -- Input stream that reads from an output stream /* PipedReader.java -- Read portion of piped character streams.
Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc. Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
This file is part of GNU Classpath. This file is part of GNU Classpath.
...@@ -24,479 +24,312 @@ resulting executable to be covered by the GNU General Public License. ...@@ -24,479 +24,312 @@ resulting executable to be covered by the GNU General Public License.
This exception does not however invalidate any other reasons why the This exception does not however invalidate any other reasons why the
executable file might be covered by the GNU General Public License. */ executable file might be covered by the GNU General Public License. */
package java.io; package java.io;
// NOTE: This implementation is very similar to that of PipedInputStream.
// If you fix a bug in here, chances are you should make a similar change to
// the PipedInputStream code.
/** /**
* This class is an input stream that reads its chars from an output stream * An input stream that reads characters from a piped writer to which it is
* to which it is connected. * connected.
* <p> * <p>
* Data is read and written to an internal buffer. It is highly recommended * Data is read and written to an internal buffer. It is highly recommended
* that the <code>PipedReader</code> and connected <code>PipedWriter</code> * that the <code>PipedReader</code> and connected <code>PipedWriter</code>
* be part of different threads. If they are not, there is a possibility * be part of different threads. If they are not, there is a possibility
* that the read and write operations could deadlock their thread. * that the read and write operations could deadlock their thread.
* *
* @version 0.0 * @specnote The JDK implementation appears to have some undocumented
* functionality where it keeps track of what thread is writing
* to pipe and throws an IOException if that thread susequently
* dies. This behaviour seems dubious and unreliable - we don't
* implement it.
* *
* @author Aaron M. Renn (arenn@urbanophile.com) * @author Aaron M. Renn (arenn@urbanophile.com)
*/ */
public class PipedReader extends Reader public class PipedReader extends Reader
{ {
/** PipedWriter to which this is connected. Null only if this
* Reader hasn't been connected yet. */
PipedWriter source;
/*************************************************************************/ /** Set to true if close() has been called on this Reader. */
boolean closed;
/*
* Class Variables
*/
/**
* The size of the internal buffer used for input/output. Note that this
* can be overriden by setting the system property
* <code>gnu.java.io.PipedReader.pipe_size</code> to the desired size shown
* in chars. This is not a standard part of the class library. Note that
* since this variable is <code>final</code>, it cannot be changed to refect
* the size specified in the property.
* <p>
* The value for this variable is 2048.
*/
private static final int PIPE_SIZE = 2048;
/** /**
* This is the real pipe size. It defaults to PIPE_SIZE, unless overridden * The size of the internal buffer used for input/output.
* by use of the system property <code>gnu.java.io.PipedReader.pipe_size</code>.
*/ */
private static int pipe_size; static final int PIPE_SIZE = 2048;
static /**
{
pipe_size = Integer.getInteger("gnu.java.io.PipedReader.pipe_size",
PIPE_SIZE).intValue();
}
/*************************************************************************/
/*
* Instance Variables
*/
/**
* This is the internal circular buffer used for storing chars written * This is the internal circular buffer used for storing chars written
* to the pipe and from which chars are read by this stream * to the pipe and from which chars are read by this stream
*/ */
private char[] buffer = new char[pipe_size]; char[] buffer = new char[PIPE_SIZE];
/** /**
* The index into buffer where the chars written char the connected * The index into buffer where the next char from the connected
* <code>PipedWriter</code> will be written. If this variables is less * <code>PipedWriter</code> will be written. If this variable is
* than 0, then the buffer is empty. If this variable is equal to * equal to <code>out</code>, then the buffer is full. If set to < 0,
* <code>out</code>, then the buffer is full * the buffer is empty.
*/ */
private int in = -1; int in = -1;
/** /**
* This index into the buffer where chars will be read from. * This index into the buffer where chars will be read from.
*/ */
private int out = 0; int out = 0;
/**
* This variable is <code>true</code> if this object has ever been connected
* to a <code>PipedWriter</code>, and <code>false</code> otherwise. It is used
* to detect an attempt to connect an already connected stream or to
* otherwise use the stream before it is connected.
*/
private boolean ever_connected = false;
/**
* This variable is set to <code>true</code> if the <code>close()</code> method is
* called. This value is checked prevents a caller from re-opening the
* stream.
*/
private boolean closed = false;
/**
* This variable is the PipedWriter to which this stream is connected.
*/
PipedWriter src;
/*************************************************************************/ /** Buffer used to implement single-argument read/receive */
char[] read_buf = new char[1];
/* /**
* Constructors * Creates a new <code>PipedReader</code> that is not connected to a
* <code>PipedWriter</code>. It must be connected before chars can
* be read from this stream.
*/ */
public PipedReader()
{
}
/** /**
* This constructor creates a new <code>PipedReader</code> that is not
* connected to a <code>PipedWriter</code>. It must be connected before
* chars can be read from this stream.
*/
public
PipedReader()
{
return;
}
/*************************************************************************/
/**
* This constructor creates a new <code>PipedReader</code> and connects * This constructor creates a new <code>PipedReader</code> and connects
* it to the passed in <code>PipedWriter</code>. The stream is then read * it to the passed in <code>PipedWriter</code>. The stream is then
* for reading. * ready for reading.
* *
* @param src The <code>PipedWriter</code> to connect this stream to * @param source The <code>PipedWriter</code> to connect this stream to
* *
* @exception IOException If an error occurs * @exception IOException If <code>source</code> is already connected.
*/
public
PipedReader(PipedWriter src) throws IOException
{
connect(src);
}
/*************************************************************************/
/*
* Instance Variables
*/ */
public PipedReader(PipedWriter source) throws IOException
{
connect(source);
}
/** /**
* This method connects this stream to the passed in <code>PipedWriter</code>. * This method connects this stream to the passed in <code>PipedWriter</code>.
* This stream is then ready for reading. If this stream is already * This stream is then ready for reading. If this stream is already
* connected or has been previously closed, then an exception is thrown * connected or has been previously closed, then an exception is thrown
* *
* @param src The <code>PipedWriter</code> to connect this stream to * @param src The <code>PipedWriter</code> to connect this stream to
* *
* @exception IOException If an error occurs * @exception IOException If this PipedReader or <code>source</code>
* has been connected already.
*/ */
public void public void connect(PipedWriter source) throws IOException
connect(PipedWriter src) throws IOException
{
if (src == this.src)
return;
if (ever_connected)
throw new IOException("Already connected");
if (closed)
throw new IOException("Stream is closed and cannot be reopened");
synchronized (lock)
{ {
src.connect(this); // The JDK (1.3) does not appear to check for a previously closed
// connection here.
ever_connected = true; if (this.source != null || source.sink != null)
} // synchronized throw new IOException ("Already connected");
}
/*************************************************************************/ source.sink = this;
this.source = source;
}
/** /**
* This methods closes the stream so that no more data can be read * This method is used by the connected <code>PipedWriter</code> to
* from it. * write chars into the buffer.
*
* @param buf The array containing chars to write to this stream
* @param offset The offset into the array to start writing from
* @param len The number of chars to write.
* *
* @exception IOException If an error occurs * @exception IOException If an error occurs
* @specnote This code should be in PipedWriter.write, but we
* put it here in order to support that bizarre recieve(int)
* method.
*/ */
public void synchronized void receive(char[] buf, int offset, int len)
close() throws IOException throws IOException
{
synchronized (lock)
{ {
closed = true; if (closed)
notifyAll(); throw new IOException ("Pipe closed");
} // synchronized
}
/*************************************************************************/ int bufpos = offset;
int copylen;
/** while (len > 0)
* This method determines whether or not this stream is ready to be read. {
* If this metho returns <code>false</code> an attempt to read may (but is try
* not guaranteed to) block. {
* while (in == out)
* @return <code>true</code> if this stream is ready to be read, <code>false</code> otherwise {
* // The pipe is full. Wake up any readers and wait for them.
* @exception IOException If an error occurs notifyAll();
*/ wait();
public boolean // The pipe could have been closed while we were waiting.
ready() throws IOException if (closed)
{ throw new IOException ("Pipe closed");
if (in == -1) }
return(false); }
catch (InterruptedException ix)
if (out == (in - 1)) {
return(false); throw new InterruptedIOException ();
}
if ((out == pipe_size) && (in == 0)) if (in < 0) // The pipe is empty.
return(false); in = 0;
return(true); // Figure out how many chars from buf can be copied without
} // overrunning out or going past the length of the buffer.
if (in < out)
copylen = Math.min (len, out - in);
else
copylen = Math.min (len, buffer.length - in);
/*************************************************************************/ // Copy chars until the pipe is filled, wrapping if neccessary.
System.arraycopy(buf, bufpos, buffer, in, copylen);
len -= copylen;
bufpos += copylen;
in += copylen;
if (in == buffer.length)
in = 0;
}
// Notify readers that new data is in the pipe.
notifyAll();
}
/** /**
* This method reads a single char from the pipe and returns it as an * This method reads chars from the stream into a caller supplied buffer.
* <code>int</code>. * It starts storing chars at position <code>offset</code> into the buffer and
* reads a maximum of <cod>>len</code> chars. Note that this method can actually
* read fewer than <code>len</code> chars. The actual number of chars read is
* returned. A -1 is returned to indicated that no chars can be read
* because the end of the stream was reached. If the stream is already
* closed, a -1 will again be returned to indicate the end of the stream.
* <p> * <p>
* This method will block if no chars are available to be read. * This method will block if no chars are available to be read.
* *
* @return An char read from the pipe, or -1 if the end of stream is * @param buf The buffer into which chars will be stored
* reached. * @param offset The index into the buffer at which to start writing.
* * @param len The maximum number of chars to read.
* @exception IOException If an error occurs.
*/ */
public int public int read() throws IOException
read() throws IOException {
{ // Method operates by calling the multichar overloaded read method
char[] buf = new char[1]; // Note that read_buf is an internal instance variable. I allocate it
// there to avoid constant reallocation overhead for applications that
// call this method in a loop at the cost of some unneeded overhead
// if this method is never called.
return(read(buf, 0, buf.length)); int r = read(read_buf, 0, 1);
}
/*************************************************************************/ if (r == -1)
return -1;
else
return read_buf[0];
}
/** /**
* This method reads chars from the stream into a caller supplied buffer. * This method reads characters from the stream into a caller supplied buffer.
* It starts storing chars at position <code>offset</code> into the buffer and * It starts storing chars at position <code>offset</code> into the buffer and
* reads a maximum of <cod>>len</code> chars. Note that this method can actually * reads a maximum of <cod>>len</code> chars. Note that this method can actually
* read fewer than <code>len</code> chars. The actual number of chars read is * read fewer than <code>len</code> chars. The actual number of chars read is
* returned. A -1 is returned to indicated that no chars can be read * returned. A -1 is returned to indicated that no chars can be read
* because the end of the stream was reached. If the stream is already * because the end of the stream was reached - ie close() was called on the
* closed, a -1 will again be returned to indicate the end of the stream. * connected PipedWriter.
* <p> * <p>
* This method will block if no chars are available to be read. * This method will block if no chars are available to be read.
* *
* @param buf The buffer into which chars will be stored * @param buf The buffer into which chars will be stored
* @param offset The index into the buffer at which to start writing. * @param offset The index into the buffer at which to start writing.
* @param len The maximum number of chars to read. * @param len The maximum number of chars to read.
*
* @exception IOException If <code>close()/code> was called on this Piped
* Reader.
*/ */
public int public synchronized int read(char[] buf, int offset, int len)
read(char[] buf, int offset, int len) throws IOException throws IOException
{ {
if (!ever_connected) if (source == null)
throw new IOException("Not connected"); throw new IOException ("Not connected");
if (closed)
throw new IOException ("Pipe closed");
synchronized (lock) // If the buffer is empty, wait until there is something in the pipe
// to read.
try
{ {
int chars_read = 0; while (in < 0)
for (;;)
{ {
// If there are chars, take them if (source.closed)
if (in != -1) return -1;
wait();
}
}
catch (InterruptedException ix)
{ {
int desired_chars = len - chars_read; throw new InterruptedIOException();
}
// We are in a "wrap" condition int total = 0;
if (out > in) int copylen;
{
if (desired_chars > (pipe_size - out)) while (true)
{ {
if (in == 0) // Figure out how many chars from the pipe can be copied without
desired_chars = (pipe_size - out) - 1; // overrunning in or going past the length of buf.
if (out < in)
copylen = Math.min (len, in - out);
else else
desired_chars = pipe_size - out; copylen = Math.min (len, buffer.length - out);
System.arraycopy(buffer, out, buf, offset + chars_read,
desired_chars);
chars_read += desired_chars; System.arraycopy (buffer, out, buf, offset, copylen);
out += desired_chars; offset += copylen;
desired_chars = len - chars_read; len -= copylen;
out += copylen;
total += copylen;
if (out == pipe_size) if (out == buffer.length)
out = 0; out = 0;
notifyAll(); if (out == in)
}
else
{ {
if ((out + desired_chars) == in) // Pipe is now empty.
--desired_chars; in = -1;
if (((out + desired_chars) == pipe_size) && (in == 0))
desired_chars = (pipe_size - out) - 1;
System.arraycopy(buffer, out, buf, offset + chars_read,
desired_chars);
chars_read += desired_chars;
out += desired_chars;
desired_chars = len - chars_read;
if (out == pipe_size)
out = 0; out = 0;
notifyAll();
}
} }
// We are in a "no wrap" or condition (can also be fall through // If output buffer is filled or the pipe is empty, we're done.
// from above if (len == 0 || in == -1)
if (in > out)
{ {
if (desired_chars >= ((in - out) - 1)) // Notify any waiting Writer that there is now space
desired_chars = (in - out) - 1; // to write.
System.arraycopy(buffer, out, buf, offset + chars_read,
desired_chars);
chars_read += desired_chars;
out += desired_chars;
desired_chars = len - chars_read;
if (out == pipe_size)
out = 0;
notifyAll(); notifyAll();
return total;
}
} }
} }
// If we are done, return public synchronized boolean ready() throws IOException
if (chars_read == len)
return(chars_read);
// Return a short count if necessary
if (chars_read > 0 && chars_read < len)
return(chars_read);
// Handle the case where the end of stream was encountered.
if (closed)
{ {
// We never let in == out so there might be one last char // The JDK 1.3 implementation does not appear to check for the closed or
// available that we have not copied yet. // unconnected stream conditions here.
if (in != -1)
{
buf[offset + chars_read] = buffer[out];
in = -1;
++out;
++chars_read;
}
if (chars_read != 0) if (in < 0)
return(chars_read); return false;
int count;
if (out < in)
count = in - out;
else else
return(-1); count = (buffer.length - out) - in;
}
// Wait for a char to be read return (count > 0);
try
{
wait();
}
catch(InterruptedException e) { ; }
} }
} // synchronized
}
/*************************************************************************/ /**
* This methods closes the stream so that no more data can be read
/** * from it.
* This method is used by the connected <code>PipedWriter</code> to
* write chars into the buffer. It uses this method instead of directly
* writing the chars in order to obtain ownership of the object's monitor
* for the purposes of calling <code>notify</code>.
*
* @param buf The array containing chars to write to this stream
* @param offset The offset into the array to start writing from
* @param len The number of chars to write.
* *
* @exception IOException If an error occurs * @exception IOException If an error occurs
*/ */
void public synchronized void close() throws IOException
write(char[] buf, int offset, int len) throws IOException
{
if (len <= 0)
return;
synchronized (lock)
{
int total_written = 0;
while (total_written < len)
{
// If we are not at the end of the buffer with out = 0
if (!((in == (buffer.length - 1)) && (out == 0)))
{
// This is the "no wrap" situation
if ((in - 1) >= out)
{
int chars_written = 0;
if ((buffer.length - in) > (len - total_written))
chars_written = (len - total_written);
else if (out == 0)
chars_written = (buffer.length - in) - 1;
else
chars_written = (buffer.length - in);
if (chars_written > 0)
System.arraycopy(buf, offset + total_written, buffer, in,
chars_written);
total_written += chars_written;
in += chars_written;
if (in == buffer.length)
in = 0;
notifyAll();
}
// This is the "wrap" situtation
if ((out > in) && (total_written != len))
{
int chars_written = 0;
// Do special processing if we are at the beginning
if (in == -1)
{
in = 0;
if (buffer.length > len)
chars_written = len;
else
chars_written = buffer.length - 1;
}
else if (((out - in) - 1) < (len - total_written))
{
chars_written = (out - in) - 1;
}
else
{ {
chars_written = len - total_written; closed = true;
} // Wake any thread which may be in receive() waiting to write data.
// If the buffer is full, wait for it to empty out
if ((out - 1) == in)
{
try
{
wait();
}
catch (InterruptedException e)
{
continue;
}
}
System.arraycopy(buf, offset + total_written, buffer, in,
chars_written);
total_written += chars_written;
in += chars_written;
if (in == buffer.length)
in = 0;
notifyAll(); notifyAll();
} }
}
// Wait for some reads to occur before we write anything.
else
{
try
{
wait();
}
catch (InterruptedException e) { ; }
}
}
} // synchronized
} }
} // class PipedReader
libjava/java/io/PipedWriter.java
/* PipedWriter.java -- Write portion of piped streams. /* PipedWriter.java -- Write portion of piped character streams.
Copyright (C) 1998 Free Software Foundation, Inc. Copyright (C) 1998, 2000, 2001 Free Software Foundation, Inc.
This file is part of GNU Classpath. This file is part of GNU Classpath.
...@@ -27,6 +27,10 @@ executable file might be covered by the GNU General Public License. */ ...@@ -27,6 +27,10 @@ executable file might be covered by the GNU General Public License. */
package java.io; 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 * This class writes its chars to a <code>PipedReader</code> to
* which it is connected. * which it is connected.
...@@ -36,182 +40,130 @@ package java.io; ...@@ -36,182 +40,130 @@ package java.io;
* they are in the same thread, read and write operations could deadlock * they are in the same thread, read and write operations could deadlock
* the thread. * the thread.
* *
* @version 0.0
*
* @author Aaron M. Renn (arenn@urbanophile.com) * @author Aaron M. Renn (arenn@urbanophile.com)
*/ */
public class PipedWriter extends Writer 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;
/*
* Instance Variables
*/
/**
* This is the <code>PipedReader</code> to which this object
* is connected.
*/
private PipedReader snk;
/** /** Buffer used to implement single-argument write */
* This flag indicates whether or not this stream has ever been char[] read_buf = new char[1];
* connected to an input stream
*/
private boolean ever_connected;
/** /**
* This flag indicates whether the <code>close</code> method has ever * Create an unconnected PipedWriter. It must be connected
* been called for this stream. * to a <code>PipedReader</code> using the <code>connect</code>
*/
private boolean closed;
/*************************************************************************/
/**
* This method initializes a new <code>PipedWriter</code> instance.
* This constructor creates an unconnected object. It must be connected
* to a <code>PipedReader</code> object using the <code>connect</code>
* method prior to writing any data or an exception will be thrown. * method prior to writing any data or an exception will be thrown.
*/ */
public public PipedWriter()
PipedWriter() {
{ }
; // Do Nothing
}
/*************************************************************************/
/** /**
* This method initializes a new <code>PipedWriter</code> instance * Create a new <code>PipedWriter</code> instance
* to write to the specified <code>PipedReader</code>. This stream * to write to the specified <code>PipedReader</code>. This stream
* is then ready for writing. * is then ready for writing.
* *
* @param snk The <code>PipedReader</code> to connect this stream to. * @param sink The <code>PipedReader</code> to connect this stream to.
* *
* @exception IOException If an error occurs * @exception IOException If <code>sink</code> has already been connected
* to a different PipedWriter.
*/ */
public public PipedWriter(PipedReader sink) throws IOException
PipedWriter(PipedReader snk) throws IOException {
{ sink.connect(this);
connect(snk); }
}
/**
/*************************************************************************/ * Connects this object to the specified <code>PipedReader</code>
* object. This stream will then be ready for writing.
/*
* Instance Methods
*/
/**
* This method connects this object to the specified
* <code>PipedReader</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>PipedReader</code> to connect this stream to * @param sink The <code>PipedReader</code> to connect this stream to
* *
* @exception IOException If an error occurs * @exception IOException If the stream has not been connected or has
* been closed.
*/ */
public void public void connect(PipedReader sink) throws IOException
connect(PipedReader snk) throws IOException {
{ if (sink != null)
if (snk == this.snk) throw new IOException ("Already connected");
return; sink.connect(this);
}
if (ever_connected)
throw new IOException("Already connected"); /**
* Write a single char of date to the stream. Note that this method will
if (closed) * block if the <code>PipedReader</code> to which this object is
throw new IOException("Stream is closed and cannot be reopened"); * connected has a full buffer.
synchronized (lock) {
this.snk = snk;
ever_connected = true;
snk.src = this;
snk.connect(this);
} // synchronized
}
/*************************************************************************/
/**
* 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
{
synchronized (lock) {
closed = true;
snk.close();
notifyAll();
} // synchronized
}
/*************************************************************************/
/**
* This methods writes a single byte of data to the pipe. This call may
* block if the pipe is full.
* *
* @param c The <code>char</code> to write, passed as an <code>int</code>. * @param b The char of data to be written, passed as an <code>int</code>.
* *
* @exception IOException If an error occurs. * @exception IOException If the stream has not been connected or has
* been closed.
*/ */
public void public void write(char b) throws IOException
write(int c) throws IOException {
{ read_buf[0] = b;
char[] buf = new char[1]; sink.receive (read_buf, 0, 1);
buf[0] = (char)c; }
write(buf, 0, buf.length);
}
/*************************************************************************/
/** /**
* This method writes <code>len</code> chars of data from the char array * 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 * <code>buf</code> starting at index <code>offset</code> in the array
* to the stream. Note that this method will block if the * to the stream. Note that this method will block if the
* <code>PipedReader</code> to which this object is connected has * <code>PipedReader</code> to which this object is connected has
* a buffer that cannot hold all of the chars to be written. * a buffer that cannot hold all of the chars to be written.
* *
* @param buf The array containing chars to write to thes stream. * @param buf The array containing chars to write to the stream.
* @param offset The index into the array to start writing chars from. * @param offset The index into the array to start writing chars from.
* @param len The number of chars to write. * @param len The number of chars to write.
* *
* @exception IOException If an error occurs * @exception IOException If the stream has not been connected or has
* been closed.
*/ */
public void public void write(char[] b, int off, int len) throws IOException
write(char[] buf, int offset, int len) throws IOException {
{ if (sink == null)
snk.write(buf, 0, len); throw new IOException ("Not connected");
} if (closed)
throw new IOException ("Pipe closed");
/*************************************************************************/ sink.receive (b, off, len);
}
/** /**
* This method flushes any unwritten chars to the underlying output * This method does nothing.
* sink. This method does nothing in this class because this class does *
* not buffer any chars. * @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()
{
}
/**
* 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 * @exception IOException If an error occurs
*/ */
public void public void close()
flush() throws IOException {
{ // A close call on an unconnected PipedWriter has no effect.
; // Do Nothing if (sink != null)
{
closed = true;
// Notify any waiting readers that the stream is now closed.
synchronized (sink)
{
sink.notifyAll();
}
}
}
} }
} // class PipedWriter
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