org.jcsp.util
Class Buffer

java.lang.Object
  org.jcsp.util.Buffer

All Implemented Interfaces:

Serializable, Cloneable, ChannelDataStore

public class Buffer
extends Object
implements ChannelDataStore, Serializable

This is used to create a buffered object channel that never loses data.

Description

Buffer is an implementation of ChannelDataStore that yields a blocking FIFO buffered semantics for a channel. See the static create methods of One2OneChannel etc.

The getState method returns EMPTY, NONEMPTYFULL or FULL according to the state of the buffer.

Author:

P.D.Austin

See Also:

ZeroBuffer, OverWriteOldestBuffer, OverWritingBuffer, OverFlowingBuffer, InfiniteBuffer, Channel, Serialized Form

Field Summary

Fields inherited from interface org.jcsp.util.ChannelDataStore

EMPTY, FULL, NONEMPTYFULL

Constructor Summary

Buffer(int size)
Construct a new Buffer with the specified size.

Method Summary

Object	clone() Returns a new (and EMPTY) Buffer with the same creation parameters as this one.
void	endGet() Removes the oldest object from the buffer.
Object	get() Returns the oldest Object from the Buffer and removes it.
int	getState() Returns the current state of the Buffer.
void	put(Object value) Puts a new Object into the Buffer.
void	removeAll() Deletes all items in the buffer, leaving it empty.
Object	startGet() Returns the oldest object from the buffer but does not remove it.

Methods inherited from class java.lang.Object

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

Constructor Detail

Buffer

public Buffer(int size)

Construct a new Buffer with the specified size.

Parameters:

size - the number of Objects the Buffer can store.

Throws:

BufferSizeError - if size is negative. Note: no action should be taken to try/catch this exception - application code generating it is in error and needs correcting.

Method Detail

get

public Object get()

Returns the oldest Object from the Buffer and removes it.

Pre-condition: getState must not currently return EMPTY.

Specified by:

get in interface ChannelDataStore

Returns:

the oldest Object from the Buffer

startGet

public Object startGet()

Returns the oldest object from the buffer but does not remove it. Pre-condition: getState must not currently return EMPTY.

Specified by:

startGet in interface ChannelDataStore

Returns:

the oldest Object from the Buffer

endGet

public void endGet()

Removes the oldest object from the buffer.

Specified by:

endGet in interface ChannelDataStore

See Also:

endGet

put

public void put(Object value)

Puts a new Object into the Buffer.

Pre-condition: getState must not currently return FULL.

Specified by:

put in interface ChannelDataStore

Parameters:

value - the Object to put into the Buffer

getState

public int getState()

Returns the current state of the Buffer.

Specified by:

getState in interface ChannelDataStore

Returns:

the current state of the Buffer (EMPTY, NONEMPTYFULL or FULL)

clone

public Object clone()

Returns a new (and EMPTY) Buffer with the same creation parameters as this one.

Note: Only the size and structure of the Buffer is cloned, not any stored data.

Specified by:

clone in interface ChannelDataStore

Overrides:

clone in class Object

Returns:

the cloned instance of this Buffer

removeAll

public void removeAll()

Description copied from interface: ChannelDataStore

Deletes all items in the buffer, leaving it empty.

Specified by:

removeAll in interface ChannelDataStore