Package org.jcsp.util
Class OverFlowingBuffer<T>
java.lang.Object
org.jcsp.util.OverFlowingBuffer<T>
- All Implemented Interfaces:
Serializable
,Cloneable
,ChannelDataStore<T>
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.
- See Also:
-
Field Summary
FieldsModifier and TypeFieldDescriptionprivate final T[]
The storage for the buffered Objectsprivate int
The number of Objects stored in the Bufferprivate int
The index of the oldest element (when counter > 0)private int
The index of the next free element (when counter invalid input: '<' buffer.length)Fields inherited from interface org.jcsp.util.ChannelDataStore
EMPTY, FULL, NONEMPTYFULL
-
Constructor Summary
ConstructorsConstructorDescriptionOverFlowingBuffer
(int size) Construct a new OverFlowingBuffer with the specified size. -
Method Summary
Modifier and TypeMethodDescriptionclone()
Returns a new (and EMPTY) OverFlowingBuffer with the same creation parameters as this one.void
endGet()
Removes the oldest object from the buffer.get()
Returns the oldest Object from the OverFlowingBuffer and removes it.int
getState()
Returns the current state of the OverFlowingBuffer.void
Puts a new Object into the OverFlowingBuffer.void
Deletes all items in the buffer, leaving it empty.startGet()
Returns the oldest object from the buffer but does not remove it.
-
Field Details
-
buffer
The storage for the buffered Objects -
counter
private int counterThe number of Objects stored in the Buffer -
firstIndex
private int firstIndexThe index of the oldest element (when counter > 0) -
lastIndex
private int lastIndexThe index of the next free element (when counter invalid input: '<' buffer.length)
-
-
Constructor Details
-
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 Details
-
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
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:
-
endGet
public void endGet()Removes the oldest object from the buffer.- Specified by:
endGet
in interfaceChannelDataStore<T>
- See Also:
-
put
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
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 classObject
- 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>
-