Package org.jcsp.util
Class InfiniteBuffer<T>
- java.lang.Object
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- org.jcsp.util.InfiniteBuffer<T>
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- All Implemented Interfaces:
java.io.Serializable
,java.lang.Cloneable
,ChannelDataStore<T>
public class InfiniteBuffer<T> extends java.lang.Object implements ChannelDataStore<T>, java.io.Serializable
This is used to create a buffered object channel that always accepts and never loses any input.Description
InfiniteBuffer is an implementation of ChannelDataStore that yields a FIFO buffered semantics for a channel. When empty, the channel blocks readers. However, its capacity is infinite (expanding to whatever is needed so far as the underlying memory system will permit). So, it never gets full and blocks a writer. See the static construction methods ofChannel
(Channel.one2one(org.jcsp.util.ChannelDataStore)
etc.).The getState method returns EMPTY or NONEMPTYFULL, but never FULL.
An initial size for the buffer can be specified during construction.
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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 InfiniteBufferprivate static int
DEFAULT_SIZE
The default size of the bufferprivate int
firstIndex
The index of the oldest element (when counter > 0)private int
initialSize
The initial size of the bufferprivate int
lastIndex
The index of the next free element (when counter < buffer.length)-
Fields inherited from interface org.jcsp.util.ChannelDataStore
EMPTY, FULL, NONEMPTYFULL
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Constructor Summary
Constructors Constructor Description InfiniteBuffer()
Construct a new InfiniteBuffer with the default size (of 8).InfiniteBuffer(int initialSize)
Construct a new InfiniteBuffer with the specified initial size.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description java.lang.Object
clone()
Returns a new (and EMPTY) InfiniteBuffer 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 InfiniteBuffer and removes it.int
getState()
Returns the current state of the InfiniteBuffer.void
put(T value)
Puts a new Object into the InfiniteBuffer.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.
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Field Detail
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DEFAULT_SIZE
private static final int DEFAULT_SIZE
The default size of the buffer- See Also:
- Constant Field Values
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initialSize
private int initialSize
The initial size of the buffer
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buffer
private T[] buffer
The storage for the buffered Objects
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counter
private int counter
The number of Objects stored in the InfiniteBuffer
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firstIndex
private int firstIndex
The index of the oldest element (when counter > 0)
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lastIndex
private int lastIndex
The index of the next free element (when counter < buffer.length)
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Constructor Detail
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InfiniteBuffer
public InfiniteBuffer()
Construct a new InfiniteBuffer with the default size (of 8).
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InfiniteBuffer
public InfiniteBuffer(int initialSize)
Construct a new InfiniteBuffer with the specified initial size.- Parameters:
initialSize
- the number of Objects the InfiniteBuffer can initially 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.
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Method Detail
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get
public T get()
Returns the oldest Object from the InfiniteBuffer and removes it.Pre-condition: getState must not currently return EMPTY.
- Specified by:
get
in interfaceChannelDataStore<T>
- Returns:
- the oldest Object from the InfiniteBuffer
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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()
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endGet
public void endGet()
Removes the oldest object from the buffer.- Specified by:
endGet
in interfaceChannelDataStore<T>
- See Also:
ChannelDataStore.startGet()
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put
public void put(T value)
Puts a new Object into the InfiniteBuffer.Implementation note: if InfiniteBuffer is full, a new internal buffer with double the capacity is constructed and the old data copied across.
- Specified by:
put
in interfaceChannelDataStore<T>
- Parameters:
value
- the Object to put into the InfiniteBuffer
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getState
public int getState()
Returns the current state of the InfiniteBuffer.- Specified by:
getState
in interfaceChannelDataStore<T>
- Returns:
- the current state of the InfiniteBuffer (EMPTY or NONEMPTYFULL)
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clone
public java.lang.Object clone()
Returns a new (and EMPTY) InfiniteBuffer with the same creation parameters as this one.Note: Only the initial size and structure of the InfiniteBuffer is cloned, not any stored data.
- Specified by:
clone
in interfaceChannelDataStore<T>
- Overrides:
clone
in classjava.lang.Object
- Returns:
- the cloned instance of this InfiniteBuffer.
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removeAll
public void removeAll()
Description copied from interface:ChannelDataStore
Deletes all items in the buffer, leaving it empty.- Specified by:
removeAll
in interfaceChannelDataStore<T>
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