Package org.jcsp.util

Class OverWritingBuffer

    • Constructor Summary

      Constructors 
      Constructor Description
      OverWritingBuffer​(int size)
      Construct a new OverWritingBuffer with the specified size.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      java.lang.Object clone()
      Returns a new (and EMPTY) OverWritingBuffer with the same creation parameters as this one.
      void endGet()
      This ends an extended rendezvous by the reader.
      java.lang.Object get()
      Returns the oldest Object from the OverWritingBuffer and removes it.
      int getState()
      Returns the current state of the OverWritingBuffer.
      void put​(java.lang.Object value)
      Puts a new Object into the OverWritingBuffer.
      void removeAll()
      Deletes all items in the buffer, leaving it empty.
      java.lang.Object startGet()
      This begins an extended rendezvous by the reader.
      • Methods inherited from class java.lang.Object

        equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • OverWritingBuffer

        public OverWritingBuffer​(int size)
        Construct a new OverWritingBuffer with the specified size.
        Parameters:
        size - the number of Objects the OverWritingBuffer can 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 OverWritingBuffer and removes it.

        Pre-condition: getState must not currently return EMPTY.

        Specified by:
        get in interface ChannelDataStore
        Returns:
        the oldest Object from the OverWritingBuffer
      • put

        public void put​(java.lang.Object value)
        Puts a new Object into the OverWritingBuffer.

        If OverWritingBuffer is full, the last item previously put into the buffer will be overwritten.

        Specified by:
        put in interface ChannelDataStore
        Parameters:
        value - the Object to put into the OverWritingBuffer
      • startGet

        public java.lang.Object startGet()
        This begins an extended rendezvous by the reader. The semantics of an extended rendezvous on an overwrite-newest buffer are slightly complicated, but hopefully intuitive.

        If the buffer is of size 2 or larger, the semantics are as follows. Beginning an extended rendezvous will return the oldest value in the buffer, but not remove it. If the writer writes to the buffer during the rendezvous, it will grow the buffer and end up overwriting the newest value as normal. At the end of the extended rendezvous, the oldest value is removed.

        If the buffer is of size 1, the semantics are identical to those of an OverWriteOldestBuffer. For a complete description, refer to the documentation for the OverWriteOldestBuffer.startGet() method.

        Specified by:
        startGet in interface ChannelDataStore
        Returns:
        The oldest value in the buffer at this time
        See Also:
        ChannelDataStore.endGet()
      • getState

        public int getState()
        Returns the current state of the OverWritingBuffer.
        Specified by:
        getState in interface ChannelDataStore
        Returns:
        the current state of the OverWritingBuffer (EMPTY or NONEMPTYFULL)
      • clone

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

        Note: Only the size and structure of the OverWritingBuffer 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 OverWritingBuffer.