java.io

Class PipedWriter

java.lang.Object

java.io.Writer

java.io.PipedWriter

All Implemented Interfaces:

Closeable, Flushable, Appendable, AutoCloseable

public class PipedWriter
extends Writer

Places 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.

See Also:

PipedReader

Field Summary

Fields inherited from class java.io.Writer

lock

Constructor Summary

Constructors

Constructor and Description
PipedWriter() Constructs a new unconnected PipedWriter.
PipedWriter(PipedReader destination) Constructs a new PipedWriter connected to destination.

Method Summary

Modifier and Type	Method and Description
void	close() Closes this writer.
void	connect(PipedReader reader) Connects this PipedWriter to a PipedReader.
void	flush() Notifies the readers of this PipedReader that characters can be read.
void	write(char[] buffer, int offset, int count) Writes count characters from the character array buffer starting at offset index to this writer.
void	write(int c) Writes a single character c to this writer.

Methods inherited from class java.io.Writer

append, append, append, nullWriter, write, write, write

Methods inherited from class java.lang.Object

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

Constructor Detail

PipedWriter

public PipedWriter()

Constructs a new unconnected PipedWriter. The resulting writer must be connected to a PipedReader before data may be written to it.

See Also:

PipedReader

PipedWriter

public PipedWriter(PipedReader destination)
            throws IOException

Constructs a new PipedWriter connected to destination. Any data written to this writer can be read from destination.

Parameters:

destination - the PipedReader to connect to.

Throws:

IOException - if destination is already connected.

Method Detail

close

public void close()
           throws IOException

Closes this writer. If a PipedReader is connected to this writer, it is closed as well and the pipe is disconnected. Any data buffered in the reader can still be read.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in class Writer

Throws:

IOException - if an error occurs while closing this writer.

connect

public void connect(PipedReader reader)
             throws IOException

Connects this PipedWriter to a PipedReader. Any data written to this writer becomes readable in the reader.

Parameters:

reader - the reader to connect to.

Throws:

IOException - if this writer is closed or already connected, or if reader is already connected.

flush

public void flush()
           throws IOException

Notifies the readers of this PipedReader that characters can be read. This method does nothing if this Writer is not connected.

Specified by:

flush in interface Flushable

Specified by:

flush in class Writer

Throws:

IOException - if an I/O error occurs while flushing this writer.

write

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

Writes count characters from the character array buffer starting at offset index to this writer. The written data can then be read from the connected PipedReader instance.

Separate threads should be used to write to a PipedWriter and to read from the connected PipedReader. If the same thread is used, a deadlock may occur.

Specified by:

write in class Writer

Parameters:

buffer - the buffer to write.

offset - the index of the first character in buffer to write.

count - the number of characters from buffer to write to this writer.

Throws:

IndexOutOfBoundsException - if offset < 0 or count < 0, or if offset + count is bigger than the length of buffer.

InterruptedIOException - if the pipe is full and the current thread is interrupted waiting for space to write data. This case is not currently handled correctly.

IOException - if this writer is closed or not connected, if the target reader is closed or if the thread reading from the target reader is no longer alive. This case is currently not handled correctly.

NullPointerException - if buffer is null.

write

public void write(int c)
           throws IOException

Writes a single character c to this writer. This character can then be read from the connected PipedReader instance.

Separate threads should be used to write to a PipedWriter and to read from the connected PipedReader. If the same thread is used, a deadlock may occur.

Overrides:

write in class Writer

Parameters:

c - the character to write.

Throws:

InterruptedIOException - if the pipe is full and the current thread is interrupted waiting for space to write data. This case is not currently handled correctly.

IOException - if this writer is closed or not connected, if the target reader is closed or if the thread reading from the target reader is no longer alive. This case is currently not handled correctly.