Package org.jcsp.util

Class InfiniteBuffer

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable, ChannelDataStore

    public class InfiniteBuffer
    extends java.lang.Object
    implements ChannelDataStore, 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.

    Author:
    P.D. Austin
    See Also:
    ZeroBuffer, Buffer, OverWriteOldestBuffer, OverWritingBuffer, OverFlowingBuffer, Channel, Serialized Form
    • 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.
      java.lang.Object get()
      Returns the oldest Object from the InfiniteBuffer and removes it.
      int getState()
      Returns the current state of the InfiniteBuffer.
      void put​(java.lang.Object value)
      Puts a new Object into the InfiniteBuffer.
      void removeAll()
      Deletes all items in the buffer, leaving it empty.
      java.lang.Object 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
    • 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 java.lang.Object 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
        Returns:
        the oldest Object from the InfiniteBuffer
      • startGet

        public java.lang.Object 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
        Returns:
        the oldest Object from the Buffer
        See Also:
        ChannelDataStore.endGet()
      • put

        public void put​(java.lang.Object 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
        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
        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
        Overrides:
        clone in class java.lang.Object
        Returns:
        the cloned instance of this InfiniteBuffer.