CSP for Java
(JCSP) 1.0-rc4

jcsp.util
Class OverFlowingBuffer

java.lang.Object
  |
  +--jcsp.util.OverFlowingBuffer
All Implemented Interfaces:
ChannelDataStore, Cloneable, Serializable

public class OverFlowingBuffer
extends Object
implements ChannelDataStore, Serializable

This is used to create a buffered object channel that always accepts input, discarding its last entered data if full.

Description

It is an implementation of ChannelDataStore that yields a FIFO buffered semantics for a channel. When empty, the channel blocks readers. When full, a writer will be accepted but the written value overflows the buffer and is lost to the channel. See the static create methods of One2OneChannel etc.

The getState method returns EMPTY or NONEMPTYFULL, but never FULL.

Author:
P.D.Austin
See Also:
ZeroBuffer, Buffer, OverWriteOldestBuffer, OverWritingBuffer, InfiniteBuffer, One2OneChannel, Any2OneChannel, One2AnyChannel, Any2AnyChannel, Serialized Form

Fields inherited from interface jcsp.util.ChannelDataStore
EMPTY, FULL, NONEMPTYFULL
 
Constructor Summary
OverFlowingBuffer(int size)
          Construct a new OverFlowingBuffer with the specified size.
 
Method Summary
 Object clone()
          Returns a new (and EMPTY) OverFlowingBuffer with the same creation parameters as this one.
 Object get()
          Returns the oldest Object from the OverFlowingBuffer and removes it.
 int getState()
          Returns the current state of the OverFlowingBuffer.
 void put(Object value)
          Puts a new Object into the OverFlowingBuffer.
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

OverFlowingBuffer

public OverFlowingBuffer(int size)
Construct a new OverFlowingBuffer with the specified size.
Parameters:
size - the number of Objects the OverFlowingBuffer can store.
Throws:
BufferSizeError - if size is zero or 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 OverFlowingBuffer and removes it.

Pre-condition: getState must not currently return EMPTY.

Specified by:
get in interface ChannelDataStore
Returns:
the oldest Object from the OverFlowingBuffer

put

public void put(Object value)
Puts a new Object into the OverFlowingBuffer.

If OverFlowingBuffer is full, the item is discarded.

Specified by:
put in interface ChannelDataStore
Parameters:
value - the Object to put into the OverFlowingBuffer

getState

public int getState()
Returns the current state of the OverFlowingBuffer.
Specified by:
getState in interface ChannelDataStore
Returns:
the current state of the OverFlowingBuffer (EMPTY or NONEMPTYFULL)

clone

public Object clone()
Returns a new (and EMPTY) OverFlowingBuffer with the same creation parameters as this one.

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

Specified by:
clone in interface ChannelDataStore
Overrides:
clone in class Object
Returns:
the cloned instance of this OverFlowingBuffer.

CSP for Java
(JCSP) 1.0-rc4

Submit a bug or feature to jcsp-team@ukc.ac.uk
Version 1.0-rc4 of the JCSP API Specification (Copyright 1997-2000 P.D.Austin and P.H.Welch - All Rights Reserved)
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