Class InfiniteBuffer<T>

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

See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private T[]
    buffer
    The storage for the buffered Objects
    private int
    counter
    The number of Objects stored in the InfiniteBuffer
    private static final int
    DEFAULT_SIZE
    The default size of the buffer
    private int
    firstIndex
    The index of the oldest element (when counter > 0)
    private int
    initialSize
    The initial size of the buffer
    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
    InfiniteBuffer()
    Construct a new InfiniteBuffer with the default size (of 8).
    InfiniteBuffer(int initialSize)
    Construct a new InfiniteBuffer with the specified initial size.

  • Method Summary

    Modifier and Type
    Method
    Description
    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.

    Methods inherited from class Object

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

  • Field Details

    • DEFAULT_SIZE

      private static final int DEFAULT_SIZE
      The default size of the buffer
      See Also:

    • initialSize

      private int initialSize
      The initial size of the buffer

    • buffer

      private T[] buffer
      The storage for the buffered Objects

    • counter

      private int counter
      The number of Objects stored in the InfiniteBuffer

    • 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

    • InfiniteBuffer

      public InfiniteBuffer()
      Construct a new InfiniteBuffer with the default size (of 8).

    • 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.

  • Method Details

    • 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 interface ChannelDataStore<T>
      Returns:
      the oldest Object from the InfiniteBuffer

    • 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 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 interface ChannelDataStore<T>
      Parameters:
      value - the Object to put into the InfiniteBuffer

    • getState

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

    • clone

      public 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 interface ChannelDataStore<T>
      Overrides:
      clone in class Object
      Returns:
      the cloned instance of this InfiniteBuffer.

    • 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>