java.io
Class PipedReader

java.lang.Object   
  java.io.Reader   
      java.io.PipedReader

All Implemented Interfaces:

Closeable , Readable

public class PipedReader
extends Reader   

Piped character-input streams.

Since:

JDK1.1

Field Summary

Fields inherited from class java.io.Reader

lock

Constructor Summary

PipedReader ()
Creates a PipedReader so that it is not yet connected.

PipedReader (PipedWriter src)
Creates a PipedReader so that it is connected to the piped writer src.

Method Summary

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 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.

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)
            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()

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

See Also:

connect(java.io.PipedWriter) , PipedWriter.connect(java.io.PipedReader)

Method Detail

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. If a thread was providing data characters to the connected piped writer, but the thread is no longer alive, then an IOException 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.

read

public int read(char[] cbuf,
                int off,
                int len)
         throws 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. This method blocks until at least one character of input is available. If a thread was providing data characters to the connected piped output, but the thread is no longer alive, then an IOException is thrown.

Specified by:

read in class 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:

IOException - if 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 an I/O error occurs

close

public void close()
           throws IOException   

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

Specified by:

close in interface Closeable

Specified by:

close in class Reader

Throws:

IOException - if an I/O error occurs.