org.jcsp.util

Class ZeroBuffer<T>

java.lang.Object

org.jcsp.util.ZeroBuffer<T>

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, ChannelDataStore<T>

public class ZeroBuffer<T>
extends java.lang.Object
implements ChannelDataStore<T>, java.io.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.

See Also:

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

Field Summary

Fields

Modifier and Type	Field and Description
private int	state The current state
private T	value The Object

Fields inherited from interface org.jcsp.util.ChannelDataStore

EMPTY, FULL, NONEMPTYFULL

Constructor Summary

Constructors

Constructor and Description
ZeroBuffer()

Method Summary

Modifier and Type	Method and Description
java.lang.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.
T	get() Returns the Object from the ZeroBuffer.
int	getState() Returns the current state of the ZeroBuffer.
void	put(T value) Puts a new Object into the ZeroBuffer.
void	removeAll() Deletes all items in the buffer, leaving it empty.
T	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

Field Detail

state

private int state

The current state

value

private T value

The Object

Constructor Detail

ZeroBuffer

public ZeroBuffer()

Method Detail

get

public T get()

Returns the Object from the ZeroBuffer.

Pre-condition: getState must not currently return EMPTY.

Specified by:

get in interface ChannelDataStore<T>

Returns:

the Object from the ZeroBuffer

startGet

public T 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<T>

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<T>

See Also:

ChannelDataStore.startGet()

put

public void put(T value)

Puts a new Object into the ZeroBuffer.

Pre-condition: getState must not currently return FULL.

Specified by:

put in interface ChannelDataStore<T>

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<T>

Returns:

the current state of the ZeroBuffer (EMPTY or FULL)

clone

public java.lang.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<T>

Overrides:

clone in class java.lang.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<T>