Package org.jcsp.util

Class InfiniteBuffer<T>

  • 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 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:
    ZeroBuffer, Buffer, OverWriteOldestBuffer, OverWritingBuffer, OverFlowingBuffer, Channel, Serialized Form

    • 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 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 < buffer.length)

    • 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

      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.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • DEFAULT_SIZE

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

      • 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 < buffer.length)

    • Constructor Detail

      • 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 Detail

      • 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:
        ChannelDataStore.endGet()

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