Module java.base

Package java.io

Class PipedReader

java.lang.Object

java.io.Reader

java.io.PipedReader

All Implemented Interfaces:

Closeable, AutoCloseable, Readable

public class PipedReader
extends Reader

Piped character-input streams.

Since:

1.1

Field Summary

Fields declared in class java.io.Reader

lock

Constructor Summary

Constructors

Constructor	Description
PipedReader()	Creates a PipedReader so that it is not yet connected.
PipedReader(int pipeSize)	Creates a PipedReader so that it is not yet connected and uses the specified pipe size for the pipe's buffer.
PipedReader(PipedWriter src)	Creates a PipedReader so that it is connected to the piped writer src.
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	Description
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	read()	Reads the next character of data from this piped stream.
int	read(char[] cbuf, int off, int len)	Reads characters into a portion of an array.
boolean	ready()	Tell whether this stream is ready to be read.

Methods declared in class java.io.Reader

mark, markSupported, nullReader, read, read, reset, skip, transferTo

Methods declared in class java.lang.Object

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

Constructor Details

PipedReader

public PipedReader(PipedWriter src)
            throws IOException

Creates a PipedReader so that it is connected to the piped writer src. Data written to src will then be available as input from this stream.

Parameters:

src - the stream to connect to.

Throws:

IOException - if an I/O error occurs.

PipedReader

public PipedReader(PipedWriter src,
 int pipeSize)
            throws 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:

IOException - if an I/O error occurs.

IllegalArgumentException - if pipeSize <= 0.

Since:

1.6

PipedReader

public PipedReader()

Creates a PipedReader so that it is not yet connected. It must be connected to a PipedWriter before being used.

PipedReader

public PipedReader(int pipeSize)

Creates a PipedReader so that it is not yet connected and uses the specified pipe size for the pipe's buffer. It must be connected to a PipedWriter before being used.

Parameters:

pipeSize - the size of the pipe's buffer.

Throws:

IllegalArgumentException - if pipeSize <= 0.

Since:

1.6

Method Details

connect

public void connect(PipedWriter src)
             throws 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:

IOException - if an I/O error occurs.

read

public int read()
         throws 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 Reader

Returns:

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

Throws:

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 IOException

Reads characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.

If len is zero, then no characters are read and 0 is returned; otherwise, there is an attempt to read at least one character. If no character is available because the stream is at its end, the value -1 is returned; otherwise, at least one character is read and stored into cbuf.

Fewer than len characters will be read if len exceeds the pipe's buffer size.

Specified by:

read in class Reader

Parameters:

cbuf - Destination buffer

off - Offset at which to start storing characters

len - Maximum number of characters to read

Returns:

The number of characters read, or -1 if the end of the stream has been reached

Throws:

IndexOutOfBoundsException - If off is negative, or len is negative, or len is greater than cbuf.length - off

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

ready

public boolean ready()
              throws 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 Reader

Returns:

True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.

Throws:

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

close

public void close()
           throws IOException

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

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in class Reader

Throws:

IOException - if an I/O error occurs.