Package org.jcsp.util
Class OverFlowingBuffer<T>
- java.lang.Object
-
- org.jcsp.util.OverFlowingBuffer<T>
-
- All Implemented Interfaces:
java.io.Serializable
,java.lang.Cloneable
,ChannelDataStore<T>
public class OverFlowingBuffer<T> extends java.lang.Object implements ChannelDataStore<T>, java.io.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 construction methods ofChannel
(Channel.one2one(org.jcsp.util.ChannelDataStore)
etc.).The getState method returns EMPTY or NONEMPTYFULL, but never FULL.
-
-
Field Summary
Fields Modifier and Type Field Description private T[]
buffer
The storage for the buffered Objectsprivate int
counter
The number of Objects stored in the Bufferprivate int
firstIndex
The index of the oldest element (when counter > 0)private int
lastIndex
The index of the next free element (when counter < buffer.length)-
Fields inherited from interface org.jcsp.util.ChannelDataStore
EMPTY, FULL, NONEMPTYFULL
-
-
Constructor Summary
Constructors Constructor Description OverFlowingBuffer(int size)
Construct a new OverFlowingBuffer with the specified size.
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description java.lang.Object
clone()
Returns a new (and EMPTY) OverFlowingBuffer with the same creation parameters as this one.void
endGet()
Removes the oldest object from the buffer.T
get()
Returns the oldest Object from the OverFlowingBuffer and removes it.int
getState()
Returns the current state of the OverFlowingBuffer.void
put(T value)
Puts a new Object into the OverFlowingBuffer.void
removeAll()
Deletes all items in the buffer, leaving it empty.T
startGet()
Returns the oldest object from the buffer but does not remove it.
-
-
-
Field Detail
-
buffer
private final T[] buffer
The storage for the buffered Objects
-
counter
private int counter
The number of Objects stored in the Buffer
-
firstIndex
private int firstIndex
The index of the oldest element (when counter > 0)
-
lastIndex
private int lastIndex
The index of the next free element (when counter < buffer.length)
-
-
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 T get()
Returns the oldest Object from the OverFlowingBuffer and removes it.Pre-condition: getState must not currently return EMPTY.
- Specified by:
get
in interfaceChannelDataStore<T>
- Returns:
- the oldest Object from the OverFlowingBuffer
-
startGet
public T 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 interfaceChannelDataStore<T>
- Returns:
- the oldest Object from the Buffer
- See Also:
ChannelDataStore.endGet()
-
endGet
public void endGet()
Removes the oldest object from the buffer.- Specified by:
endGet
in interfaceChannelDataStore<T>
- See Also:
ChannelDataStore.startGet()
-
put
public void put(T value)
Puts a new Object into the OverFlowingBuffer.If OverFlowingBuffer is full, the item is discarded.
- Specified by:
put
in interfaceChannelDataStore<T>
- Parameters:
value
- the Object to put into the OverFlowingBuffer
-
getState
public int getState()
Returns the current state of the OverFlowingBuffer.- Specified by:
getState
in interfaceChannelDataStore<T>
- Returns:
- the current state of the OverFlowingBuffer (EMPTY or NONEMPTYFULL)
-
clone
public java.lang.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 interfaceChannelDataStore<T>
- Overrides:
clone
in classjava.lang.Object
- Returns:
- the cloned instance of this OverFlowingBuffer.
-
removeAll
public void removeAll()
Description copied from interface:ChannelDataStore
Deletes all items in the buffer, leaving it empty.- Specified by:
removeAll
in interfaceChannelDataStore<T>
-
-