uk.org.ogsadai.engine
Class SynchronizedPipe

java.lang.Object
  |
  +--uk.org.ogsadai.engine.SynchronizedPipe

All Implemented Interfaces:

BlockReader, BlockWriter, Pipe

public class SynchronizedPipe

extends java.lang.Object

implements Pipe

A simple fixed-sized synchronized pipe that uses a circular buffer to store blocks of data. The producer and consumer threads that use the pipe should be distinct.

Author:

The OGSA-DAI Project Team

COPYRIGHT_NOTICE

private static final java.lang.String COPYRIGHT_NOTICE

Copyright statement.

See Also:

Constant Field Values

mBuffer

private final CircularBuffer mBuffer

Stores the blocks contained in the pipe.

mNext

private java.lang.Object mNext

The next block to return.

mFirstCall

private boolean mFirstCall

Indicates the first time the hasNext method is invoked.

SynchronizedPipe

public SynchronizedPipe(int bufferSize)

Constructs a synchronized pipe of the specified fixed size.

Parameters:

bufferSize - The number of blocks that the pipe can store before blocking.

next

public java.lang.Object next()

Description copied from interface: BlockReader

Gets the next block of data contained in the block reader.

Specified by:

next in interface BlockReader

Returns:

an Object

nextBlock

private java.lang.Object nextBlock()

Gets the next block or null if there are no more blocks.

Returns:

next block or null.

readNext

private void readNext()

Reads the next block from the circular buffer, blocking until a block becomes available or the pipe is closed.

hasNext

public boolean hasNext()

Description copied from interface: BlockReader

Indicates whether or not there are any more blocks of data to be read from the block reader.

Specified by:

hasNext in interface BlockReader

Returns:

true if there are more blocks to be read or false otherwise

put

public void put(java.lang.Object block)

Description copied from interface: BlockWriter

Writes the specified block of output data.

Specified by:

put in interface BlockWriter

Parameters:

block - the Object block to write

close

public void close()

Description copied from interface: BlockWriter

Closes the block writer to indicate that there are no more blocks are to be written. After close has been called, the put method should no longer be used.

Specified by:

close in interface BlockWriter

isOpen

public boolean isOpen()

Description copied from interface: BlockWriter

Indicates whether or not the block writer is open for writing via the put method. After the close method has been invoked this method should return false.

Specified by:

isOpen in interface BlockWriter

Returns:

A boolean value indicating whether this block writer is open for writing