java.io
Class PipedReader

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

All Implemented Interfaces:

Closeable, Readable

public class PipedReader
extends Reader

PipedReader is a class which receives information on a communications pipe. When two threads want to pass data back and forth, one creates a piped writer and the other creates a piped reader.

Field Summary

Fields inherited from class java.io.Reader

lock

Constructor Summary

PipedReader()
Constructs a new unconnected PipedReader.

PipedReader(PipedWriter out)
Constructs a new PipedReader connected to the PipedWriter out.

Method Summary

void	close() Close this PipedReader.
void	connect(PipedWriter src) Connects this PipedReader to a PipedWriter.
(package private) void	done()
(package private) void	establishConnection() Establish the connection to the PipedWriter.
(package private) void	flush()
int	read() Reads the next character from this Reader.
int	read(char[] buffer, int offset, int count) Reads at most count character from this PipedReader and stores them in char array buffer starting at offset.
boolean	ready() Answer a boolean indicating whether or not this Reader is ready to be read.
(package private) void	receive(char oneChar) Receives a char and stores it into the PipedReader.
(package private) void	receive(char[] chars, int offset, int count) Receives a char array and stores it into the PipedReader.

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()

Constructs a new unconnected PipedReader. The resulting Reader must be connected to a PipedWriter before data may be read from it.

PipedReader

public PipedReader(PipedWriter out)
            throws IOException

Constructs a new PipedReader connected to the PipedWriter out. Any data written to the writer can be read from the this reader.

Parameters:

out - the PipedWriter to connect to.

Throws:

IOException - if this or out are already connected.

Method Detail

close

public void close()
           throws IOException

Close this PipedReader. This implementation releases the buffer used for the pipe and notifies all threads waiting to read or write.

Specified by:

close in interface Closeable

Specified by:

close in class Reader

Throws:

IOException - If an error occurs attempting to close this reader.

connect

public void connect(PipedWriter src)
             throws IOException

Connects this PipedReader to a PipedWriter. Any data written to the Writer becomes available in this Reader.

Parameters:

src - the source PipedWriter.

Throws:

IOException - If either Writer or Reader is already connected.

establishConnection

void establishConnection()
                   throws IOException

Establish the connection to the PipedWriter.

Throws:

IOException - If this Reader is already connected.

read

public int read()
         throws IOException

Reads the next character from this Reader. Answer the character actually read or -1 if no character was read and end of reader was encountered. Separate threads should be used for the reader of the PipedReader and the PipedWriter. There may be undesirable results if more than one Thread interacts a reader or writer pipe.

Overrides:

read in class Reader

Returns:

int the character read -1 if end of reader.

Throws:

IOException - If the reader is already closed or another IOException occurs.

read

public int read(char[] buffer,
                int offset,
                int count)
         throws IOException

Reads at most count character from this PipedReader and stores them in char array buffer starting at offset. Answer the number of characters actually read or -1 if no characters were read and end of stream was encountered. Separate threads should be used for the reader of the PipedReader and the PipedWriter. There may be undesirable results if more than one Thread interacts a reader or writer pipe.

Specified by:

read in class Reader

Parameters:

buffer - the character array in which to store the read characters.

offset - the offset in buffer to store the read characters.

count - the maximum number of characters to store in buffer.

Returns:

int the number of characters actually read or -1 if end of reader.

Throws:

IOException - If the reader is already closed or another IOException occurs.

ready

public boolean ready()
              throws IOException

Answer a boolean indicating whether or not this Reader is ready to be read. Returns true if the buffer contains characters to be read.

Overrides:

ready in class Reader

Returns:

boolean true if there are characters ready, false otherwise.

Throws:

IOException - If the reader is already closed or another IOException occurs.

receive

void receive(char oneChar)
       throws IOException

Receives a char and stores it into the PipedReader. This called by PipedWriter.write() when writes occur.

If the buffer is full and the thread sending #receive is interrupted, the InterruptedIOException will be thrown.

Parameters:

oneChar - the char to store into the pipe.

Throws:

IOException - If the stream is already closed or another IOException occurs.

receive

void receive(char[] chars,
             int offset,
             int count)
       throws IOException

Receives a char array and stores it into the PipedReader. This called by PipedWriter.write() when writes occur.

If the buffer is full and the thread sending #receive is interrupted, the InterruptedIOException will be thrown.

Parameters:

chars - the char array to store into the pipe.

offset - offset to start reading from

count - total characters to read

Throws:

IOException - If the stream is already closed or another IOException occurs.

done

void done()

flush

void flush()