Class PriorityQueue<T>

  • public abstract class PriorityQueue<T>
    extends Object
    • Field Detail

      • size

        protected int size
      • maxSize

        protected final int maxSize
    • Constructor Detail

      • PriorityQueue

        public PriorityQueue​(int maxSize)
      • PriorityQueue

        public PriorityQueue​(int maxSize,
                             boolean prepopulate)
    • Method Detail

      • lessThan

        protected abstract boolean lessThan​(T a,
                                            T b)
        Determines the ordering of objects in this priority queue. Subclasses must define this one method.
        true iff parameter a is less than parameter b.
      • getSentinelObject

        protected T getSentinelObject()
      • add

        public final T add​(T element)
        Adds an Object to a PriorityQueue in log(size) time. If one tries to add more objects than maxSize from initialize an
        the new 'top' element in the queue.
      • insertWithOverflow

        public T insertWithOverflow​(T element)
        Adds an Object to a PriorityQueue in log(size) time. It returns the object (if any) that was dropped off the heap because it was full. This can be the given parameter (in case it is smaller than the full heap's minimum, and couldn't be added), or another object that was previously the smallest value in the heap and now has been replaced by a larger one, or null if the queue wasn't yet full with maxSize elements.
      • top

        public final T top()
        Returns the least element of the PriorityQueue in constant time.
      • pop

        public final T pop()
        Removes and returns the least element of the PriorityQueue in log(size) time.
      • updateTop

        public final T updateTop()
        Should be called when the Object at top changes values. Still log(n) worst case, but it's at least twice as fast to;
        instead of
         o = pq.pop();
        the new 'top' element.
      • size

        public final int size()
        Returns the number of elements currently stored in the PriorityQueue.
      • clear

        public final void clear()
        Removes all entries from the PriorityQueue.
      • getHeapArray

        public final Object[] getHeapArray()
        This method returns the internal heap array as Object[].
        NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.