org.jcsp.util
Class ZeroBuffer

java.lang.Object
  org.jcsp.util.ZeroBuffer

All Implemented Interfaces:

Serializable, Cloneable, ChannelDataStore

public class ZeroBuffer
extends Object
implements ChannelDataStore, Serializable

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

Description

ZeroBuffer is an implementation of ChannelDataStore that yields the standard CSP semantics for a channel -- that is zero buffered with direct synchronisation between reader and writer. Unless specified otherwise, this is the default behaviour for channels. See the static construction methods of Channel (Channel.one2one(org.jcsp.util.ChannelDataStore) etc.).

The getState method will return FULL if there is an output waiting on the channel and EMPTY if there is not.

Author:

P.D. Austin

See Also:

Buffer, OverWriteOldestBuffer, OverWritingBuffer, OverFlowingBuffer, InfiniteBuffer, One2OneChannelImpl, Any2OneChannelImpl, One2AnyChannelImpl, Any2AnyChannelImpl, Serialized Form

Field Summary

Fields inherited from interface org.jcsp.util.ChannelDataStore

EMPTY, FULL, NONEMPTYFULL

Constructor Summary

ZeroBuffer()

Method Summary

Object	clone() Returns a new (and EMPTY) ZeroBuffer with the same creation parameters as this one.
void	endGet() Ends the extended rendezvous by clearing the buffer.
Object	get() Returns the Object from the ZeroBuffer.
int	getState() Returns the current state of the ZeroBuffer.
void	put(Object value) Puts a new Object into the ZeroBuffer.
void	removeAll() Deletes all items in the buffer, leaving it empty.
Object	startGet() Begins an extended rendezvous - simply returns the next object in the buffer.

Methods inherited from class java.lang.Object

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

Constructor Detail

ZeroBuffer

public ZeroBuffer()

Method Detail

get

public Object get()

Returns the Object from the ZeroBuffer.

Pre-condition: getState must not currently return EMPTY.

Specified by:

get in interface ChannelDataStore

Returns:

the Object from the ZeroBuffer

startGet

public Object startGet()

Begins an extended rendezvous - simply returns the next object in the buffer. This function does not remove the object. Pre-condition: getState must not currently return EMPTY.

Specified by:

startGet in interface ChannelDataStore

Returns:

The object in the buffer.

See Also:

ChannelDataStore.endGet()

endGet

public void endGet()

Ends the extended rendezvous by clearing the buffer.

Specified by:

endGet in interface ChannelDataStore

See Also:

ChannelDataStore.startGet()

put

public void put(Object value)

Puts a new Object into the ZeroBuffer.

Pre-condition: getState must not currently return FULL.

Specified by:

put in interface ChannelDataStore

Parameters:

value - the Object to put into the ZeroBuffer

getState

public int getState()

Returns the current state of the ZeroBuffer.

Specified by:

getState in interface ChannelDataStore

Returns:

the current state of the ZeroBuffer (EMPTY or FULL)

clone

public Object clone()

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

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

Specified by:

clone in interface ChannelDataStore

Overrides:

clone in class Object

Returns:

the cloned instance of this ZeroBuffer.

removeAll

public void removeAll()

Description copied from interface: ChannelDataStore

Deletes all items in the buffer, leaving it empty.

Specified by:

removeAll in interface ChannelDataStore