org.ka2ddo.yaac.io

Class PipedReader

java.lang.Object

java.io.Reader

org.ka2ddo.yaac.io.PipedReader

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, java.lang.Readable

public class PipedReader
extends java.io.Reader

This is a performance-optimized clone of the java.io.PipedReader class.

Author:

Andrew Pavlin, KA2DDO

Field Summary

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors

Constructor and Description
PipedReader(PipedWriter src, int pipeSize) Creates a PipedReader so that it is connected to the piped writer src and uses the specified pipe size for the pipe's buffer.

Method Summary

Modifier and Type	Method and Description
void	clearStatistics() Reset the statistics counters.
void	close() Closes this piped stream and releases any system resources associated with the stream.
void	connect(PipedWriter src) Causes this piped reader to be connected to the piped writer src.
int	getNumEmpty() Report the number of times the pipe was found empty.
int	getNumFull() Report the number of times the pipe was found full.
long	getWaitOnEmpty() Report the number of milliseconds spent waiting on an empty pipe.
long	getWaitOnFull() Report the number of milliseconds spent waiting on a full pipe.
int	read() Reads the next character of data from this piped stream.
int	read(char[] cbuf, int off, int len) Reads up to len characters of data from this piped stream into an array of characters.
boolean	ready() Tell whether this stream is ready to be read.
void	receive(char[] c, int off, int len) Receives data into an array of characters.
void	setReaderThread() Mark the thread that is reading from the pipe.

Methods inherited from class java.io.Reader

mark, markSupported, read, read, reset, skip

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PipedReader

public PipedReader(PipedWriter src,
                   int pipeSize)
            throws java.io.IOException

Creates a PipedReader so that it is connected to the piped writer src and uses the specified pipe size for the pipe's buffer. Data written to src will then be available as input from this stream.

Parameters:

src - the stream to connect to.

pipeSize - the size of the pipe's buffer.

Throws:

java.io.IOException - if an I/O error occurs.

java.lang.IllegalArgumentException - if pipeSize <= 0.

Method Detail

connect

public void connect(PipedWriter src)
             throws java.io.IOException

Causes this piped reader to be connected to the piped writer src. If this object is already connected to some other piped writer, an IOException is thrown.

If src is an unconnected piped writer and snk is an unconnected piped reader, they may be connected by either the call:

snk.connect(src) 

or the call:

src.connect(snk) 

The two calls have the same effect.

Parameters:

src - The piped writer to connect to.

Throws:

java.io.IOException - if an I/O error occurs.

receive

public void receive(char[] c,
                    int off,
                    int len)
             throws java.io.IOException

Receives data into an array of characters. This method will block until there is room to write some input. This method requires that the single writer thread register itself with setWriterThread() prior to first calling this method.

Parameters:

c - the data.

off - the start offset in the data.

len - the number of characters to write.

Throws:

java.io.IOException - if the pipe is broken, unconnected, closed or an I/O error occurs.

setReaderThread

public void setReaderThread()

Mark the thread that is reading from the pipe.

read

public int read()
         throws java.io.IOException

Reads the next character of data from this piped stream. If no character is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

Overrides:

read in class java.io.Reader

Returns:

the next character of data, or -1 if the end of the stream is reached.

Throws:

java.io.IOException - if the pipe is broken, unconnected, closed, or an I/O error occurs.

read

public int read(char[] cbuf,
                int off,
                int len)
         throws java.io.IOException

Reads up to len characters of data from this piped stream into an array of characters. Less than len characters will be read if the end of the data stream is reached or if len exceeds the pipe's buffer size. This method blocks until at least one character of input is available.

Specified by:

read in class java.io.Reader

Parameters:

cbuf - the buffer into which the data is read.

off - the start offset of the data.

len - the maximum number of characters read.

Returns:

the total number of characters read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Throws:

java.io.IOException - if the pipe is broken, unconnected, closed, or an I/O error occurs.

ready

public boolean ready()
              throws java.io.IOException

Tell whether this stream is ready to be read. A piped character stream is ready if the circular buffer is not empty.

Overrides:

ready in class java.io.Reader

Throws:

java.io.IOException - if the pipe is broken, unconnected, or closed.

close

public void close()
           throws java.io.IOException

Closes this piped stream and releases any system resources associated with the stream.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in class java.io.Reader

Throws:

java.io.IOException - if an I/O error occurs.

getNumEmpty

public int getNumEmpty()

Report the number of times the pipe was found empty.

Returns:

empty count

getWaitOnEmpty

public long getWaitOnEmpty()

Report the number of milliseconds spent waiting on an empty pipe.

Returns:

wait time in milliseconds

getNumFull

public int getNumFull()

Report the number of times the pipe was found full.

Returns:

full count

getWaitOnFull

public long getWaitOnFull()

Report the number of milliseconds spent waiting on a full pipe.

Returns:

wait time in milliseconds

clearStatistics

public void clearStatistics()

Reset the statistics counters.