Package org.jcsp.util

Class OverWritingBuffer<T>

    • 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 T 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<T>
        Returns:
        the oldest Object from the OverWritingBuffer
      • put

        public void put​(T 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<T>
        Parameters:
        value - the Object to put into the OverWritingBuffer
      • startGet

        public T 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<T>
        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<T>
        Returns:
        the current state of the OverWritingBuffer (EMPTY or NONEMPTYFULL)
      • clone

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