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[]
    The storage for the buffered Objects
    private int
    The number of Objects stored in the Buffer
    private int
    The index of the oldest element (when counter > 0)
    private int
    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
    Buffer(int size)
    Construct a new Buffer with the specified size.
  • Method Summary

    Modifier and Type
    Method
    Description
    Returns a new (and EMPTY) Buffer with the same creation parameters as this one.
    void
    Removes the oldest object from the buffer.
    get()
    Returns the oldest Object from the Buffer and removes it.
    int
    Returns the current state of the Buffer.
    void
    put(T value)
    Puts a new Object into the Buffer.
    void
    Deletes all items in the buffer, leaving it empty.
    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 < 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>