Package org.jcsp.util

Class Buffer<T>

java.lang.Object
org.jcsp.util.Buffer<T>
All Implemented Interfaces:
Serializable, Cloneable, ChannelDataStore<T>
public class Buffer<T> extends Object implements ChannelDataStore<T>, Serializable
This is used to create a buffered object channel that never loses data.

Description

Buffer is an implementation of ChannelDataStore that yields a blocking FIFO buffered semantics for a channel. See the static construction methods of Channel (Channel.one2one(org.jcsp.util.ChannelDataStore) etc.).

The getState method returns EMPTY, NONEMPTYFULL or FULL according to the state of the buffer.

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 org.jcsp.util.ChannelDataStore

    EMPTY, FULL, NONEMPTYFULL

  • Constructor Summary

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

  • Method Summary

    Modifier and Type
    Method
    Description
    Object
    clone()
    Returns a new (and EMPTY) Buffer 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 Buffer and removes it.
    int
    getState()
    Returns the current state of the Buffer.
    void
    put(T value)
    Puts a new Object into the Buffer.
    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 java.lang.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

    • Buffer

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

      Pre-condition: getState must not currently return EMPTY.

      Specified by:
      get in interface ChannelDataStore<T>
      Returns:
      the oldest Object from the Buffer

    • 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 Buffer.

      Pre-condition: getState must not currently return FULL.

      Specified by:
      put in interface ChannelDataStore<T>
      Parameters:
      value - the Object to put into the Buffer

    • getState

      public int getState()
      Returns the current state of the Buffer.
      Specified by:
      getState in interface ChannelDataStore<T>
      Returns:
      the current state of the Buffer (EMPTY, NONEMPTYFULL or FULL)

    • clone

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

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

      Specified by:
      clone in interface ChannelDataStore<T>
      Overrides:
      clone in class Object
      Returns:
      the cloned instance of this Buffer

    • 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>