Class OverFlowingBuffer<T>

java.lang.Object
org.jcsp.util.OverFlowingBuffer<T>
All Implemented Interfaces:
Serializable, Cloneable, ChannelDataStore<T>
public class OverFlowingBuffer<T> extends Object implements ChannelDataStore<T>, 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 of Channel (Channel.one2one(org.jcsp.util.ChannelDataStore) etc.).

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

See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private final T[]
    buffer
    The storage for the buffered Objects
    private int
    counter
    The number of Objects stored in the Buffer
    private int
    firstIndex
    The index of the oldest element (when counter > 0)
    private int
    lastIndex
    The index of the next free element (when counter invalid input: '<' buffer.length)

    Fields inherited from interface ChannelDataStore

    EMPTY, FULL, NONEMPTYFULL

  • Constructor Summary

    Constructors
    Constructor
    Description
    OverFlowingBuffer(int size)
    Construct a new OverFlowingBuffer with the specified size.

  • Method Summary

    Modifier and Type
    Method
    Description
    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.

    Methods inherited from class Object

    equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • 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 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

      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 interface ChannelDataStore<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 interface ChannelDataStore<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 interface ChannelDataStore<T>
      See Also:

    • 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 interface ChannelDataStore<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 interface ChannelDataStore<T>
      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<T>
      Overrides:
      clone in class 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 interface ChannelDataStore<T>