Package info.monitorenter.util.collections

Class RingBufferArray<T>

java.lang.Object
info.monitorenter.util.collections.RingBufferArrayFast<T>
info.monitorenter.util.collections.RingBufferArray<T>
Type Parameters:
T - the type to store.
All Implemented Interfaces:
IRingBuffer<T>, Serializable, Cloneable, Iterable<T>
public class RingBufferArray<T> extends RingBufferArrayFast<T>
A RingBuffer can be used to store a limited number of entries of any type within a buffer.

As soon as the maximum number of entries is reached, the next entry is added to the end and the first entry is removed from it. In this case, all elements are stored in a Object[]. But don't worry there will not be a single call to System.arraycopy caused by invocation of the add(Object element)- method. Internal indexes into the array for the head and tail allow to reuse the same memory again and again.
No element is lost: If setBufferSize(int asize) decreases the size of the buffer and it will get smaller than the actual amount of elements stored, they will get cached until removed.

For allowing high performance single-threaded use this implementation and the implementations of the retrievable Iterator- instances are not synchronized at all.

Version:
$Revision: 1.10 $
Author:
Achim Westermann
See Also:

  • Field Details

    • m_pendingremove

      protected List<T> m_pendingremove
      Elements that stores elements that have to be removed due to an invocation to setBufferSize(int) with a smaller argument than the amount of elements stored.

  • Constructor Details

    • RingBufferArray

      public RingBufferArray(int aSize)
      Constructs a RingBuffer with the given size.

      Parameters:
      aSize - the size of the buffer.

  • Method Details

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class RingBufferArrayFast<T>
      See Also:

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class RingBufferArrayFast<T>
      See Also:

    • isEmpty

      public boolean isEmpty()
      Description copied from interface: IRingBuffer
      Tests whether no elements are stored in the buffer.

      Specified by:
      isEmpty in interface IRingBuffer<T>
      Overrides:
      isEmpty in class RingBufferArrayFast<T>
      Returns:
      true if no element is stored in the buffer.
      See Also:

    • iteratorF2L

      public Iterator<T> iteratorF2L()
      Description copied from class: RingBufferArrayFast
      Returns an Iterator that will return the elements in exactly the inverse order the subsequent call to remove() would do.

      The youngest elements are returned first. The Iterator returned is not thread- safe!

      Specified by:
      iteratorF2L in interface IRingBuffer<T>
      Overrides:
      iteratorF2L in class RingBufferArrayFast<T>
      Returns:
      an Iterator that will return the elements in exactly the inverse order the subsequent call to remove() would do.
      See Also:

    • iteratorL2F

      public Iterator<T> iteratorL2F()
      Description copied from class: RingBufferArrayFast
      Returns an Iterator that will return the elements in exactly the order the subsequent call to remove() would do.

      The oldest elements are returned first. The Iterator returned is not thread- safe!

      Specified by:
      iteratorL2F in interface IRingBuffer<T>
      Overrides:
      iteratorL2F in class RingBufferArrayFast<T>
      Returns:
      an Iterator that will return the elements in exactly the order the subsequent call to remove() would do.
      See Also:

    • remove

      public T remove()
      Description copied from interface: IRingBuffer
      Removes the oldest element from the buffer.

      Specified by:
      remove in interface IRingBuffer<T>
      Overrides:
      remove in class RingBufferArrayFast<T>
      Returns:
      the removed oldest element from the buffer.
      See Also:

    • removeAll

      public T[] removeAll()
      Description copied from interface: IRingBuffer
      Clears the buffer. It will return all of it's stored elements.

      Specified by:
      removeAll in interface IRingBuffer<T>
      Overrides:
      removeAll in class RingBufferArrayFast<T>
      Returns:
      all removed elements.
      See Also:

    • setBufferSize

      public void setBufferSize(int newSize)
      Sets a new buffer- size.

      A new size is assigned but the elements "overhanging" are returned by the Object remove()- method first. This may take time until the buffer has its actual size again. Don't pretend on calling this method for saving of memory very often as the whole buffer has to be copied into a new array every time- and if newSize < getSize() additional the overhanging elements references have to be moved to the internal List pendingremove.

      Specified by:
      setBufferSize in interface IRingBuffer<T>
      Overrides:
      setBufferSize in class RingBufferArrayFast<T>
      Parameters:
      newSize - the new size of the buffer.

    • size

      public int size()
      Description copied from interface: IRingBuffer
      Returns the actual amount of elements stored in the buffer.

      Specified by:
      size in interface IRingBuffer<T>
      Overrides:
      size in class RingBufferArrayFast<T>
      Returns:
      the actual amount of elements stored in the buffer.
      See Also:

    • toString

      public String toString()
      Returns a string representation of the RingBuffer and it's contents.

      Don't call this in your application too often: hard array copy - operation and memory allocations are triggered.

      Overrides:
      toString in class RingBufferArrayFast<T>
      Returns:
      a string representation of the RingBuffer and it's contents.