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PipedOutputStream.javaAPI DocJava SE 5 API5452Fri Aug 26 14:57:00 BST 2005java.io

PipedOutputStream

public class PipedOutputStream extends OutputStream
A piped output stream can be connected to a piped input stream to create a communications pipe. The piped output stream is the sending end of the pipe. Typically, data is written to a PipedOutputStream object by one thread and data is read from the connected PipedInputStream by some other thread. Attempting to use both objects from a single thread is not recommended as it may deadlock the thread.
author
James Gosling
version
1.26, 12/19/03
see
java.io.PipedInputStream
since
JDK1.0

Fields Summary
private PipedInputStream
sink
Constructors Summary
public PipedOutputStream(PipedInputStream snk)
Creates a piped output stream connected to the specified piped input stream. Data bytes written to this stream will then be available as input from snk.

param
snk The piped input stream to connect to.
exception
IOException if an I/O error occurs.

	connect(snk);
    
public PipedOutputStream()
Creates a piped output stream that is not yet connected to a piped input stream. It must be connected to a piped input stream, either by the receiver or the sender, before being used.

see
java.io.PipedInputStream#connect(java.io.PipedOutputStream)
see
java.io.PipedOutputStream#connect(java.io.PipedInputStream)

    
Methods Summary
public voidclose()
Closes this piped output stream and releases any system resources associated with this stream. This stream may no longer be used for writing bytes.

exception
IOException if an I/O error occurs.

	if (sink != null) {
	    sink.receivedLast();
	}
    
public synchronized voidconnect(java.io.PipedInputStream snk)
Connects this piped output stream to a receiver. If this object is already connected to some other piped input stream, an IOException is thrown.

If snk is an unconnected piped input stream and src is an unconnected piped output stream, they may be connected by either the call:

src.connect(snk)
or the call:
snk.connect(src)
The two calls have the same effect.

param
snk the piped input stream to connect to.
exception
IOException if an I/O error occurs.

        if (snk == null) {
            throw new NullPointerException();
        } else if (sink != null || snk.connected) {
	    throw new IOException("Already connected");
	}
	sink = snk;
	snk.in = -1;
	snk.out = 0;
        snk.connected = true;
    
public synchronized voidflush()
Flushes this output stream and forces any buffered output bytes to be written out. This will notify any readers that bytes are waiting in the pipe.

exception
IOException if an I/O error occurs.

	if (sink != null) {
            synchronized (sink) {
                sink.notifyAll();
            }
	}
    
public voidwrite(int b)
Writes the specified byte to the piped output stream. If a thread was reading data bytes from the connected piped input stream, but the thread is no longer alive, then an IOException is thrown.

Implements the write method of OutputStream.

param
b the byte to be written.
exception
IOException if an I/O error occurs.

        if (sink == null) {
            throw new IOException("Pipe not connected");
        }
	sink.receive(b);
    
public voidwrite(byte[] b, int off, int len)
Writes len bytes from the specified byte array starting at offset off to this piped output stream. If a thread was reading data bytes from the connected piped input stream, but the thread is no longer alive, then an IOException is thrown.

param
b the data.
param
off the start offset in the data.
param
len the number of bytes to write.
exception
IOException if an I/O error occurs.

        if (sink == null) {
            throw new IOException("Pipe not connected");
        } else if (b == null) {
	    throw new NullPointerException();
	} else if ((off < 0) || (off > b.length) || (len < 0) ||
		   ((off + len) > b.length) || ((off + len) < 0)) {
	    throw new IndexOutOfBoundsException();
	} else if (len == 0) {
	    return;
	} 
	sink.receive(b, off, len);