Class ObjectArrayPriorityQueue<K>

  • All Implemented Interfaces:
    PriorityQueue<K>, Serializable

    public class ObjectArrayPriorityQueue<K>
    extends Object
    implements PriorityQueue<K>, Serializable
    A type-specific array-based priority queue.

    Instances of this class represent a priority queue using a backing array—all operations are performed directly on the array. The array is enlarged as needed, but it is never shrunk. Use the trim() method to reduce its size, if necessary.

    This implementation is extremely inefficient, but it is difficult to beat when the size of the queue is very small.

    See Also:
    Serialized Form
    • Constructor Detail

      • ObjectArrayPriorityQueue

        public ObjectArrayPriorityQueue​(int capacity,
                                        Comparator<? super K> c)
        Creates a new empty queue with a given capacity and comparator.
        Parameters:
        capacity - the initial capacity of this queue.
        c - the comparator used in this queue, or null for the natural order.
      • ObjectArrayPriorityQueue

        public ObjectArrayPriorityQueue​(int capacity)
        Creates a new empty queue with a given capacity and using the natural order.
        Parameters:
        capacity - the initial capacity of this queue.
      • ObjectArrayPriorityQueue

        public ObjectArrayPriorityQueue​(Comparator<? super K> c)
        Creates a new empty queue with a given comparator.
        Parameters:
        c - the comparator used in this queue, or null for the natural order.
      • ObjectArrayPriorityQueue

        public ObjectArrayPriorityQueue()
        Creates a new empty queue using the natural order.
      • ObjectArrayPriorityQueue

        public ObjectArrayPriorityQueue​(K[] a,
                                        int size,
                                        Comparator<? super K> c)
        Wraps a given array in a queue using a given comparator.

        The queue returned by this method will be backed by the given array.

        Parameters:
        a - an array.
        size - the number of elements to be included in the queue.
        c - the comparator used in this queue, or null for the natural order.
      • ObjectArrayPriorityQueue

        public ObjectArrayPriorityQueue​(K[] a,
                                        Comparator<? super K> c)
        Wraps a given array in a queue using a given comparator.

        The queue returned by this method will be backed by the given array.

        Parameters:
        a - an array.
        c - the comparator used in this queue, or null for the natural order.
      • ObjectArrayPriorityQueue

        public ObjectArrayPriorityQueue​(K[] a,
                                        int size)
        Wraps a given array in a queue using the natural order.

        The queue returned by this method will be backed by the given array.

        Parameters:
        a - an array.
        size - the number of elements to be included in the queue.
      • ObjectArrayPriorityQueue

        public ObjectArrayPriorityQueue​(K[] a)
        Wraps a given array in a queue using the natural order.

        The queue returned by this method will be backed by the given array.

        Parameters:
        a - an array.
    • Method Detail

      • enqueue

        public void enqueue​(K x)
        Description copied from interface: PriorityQueue
        Enqueues a new element.
        Specified by:
        enqueue in interface PriorityQueue<K>
        Parameters:
        x - the element to enqueue.
      • dequeue

        public K dequeue()
        Description copied from interface: PriorityQueue
        Dequeues the first element from the queue.
        Specified by:
        dequeue in interface PriorityQueue<K>
        Returns:
        the dequeued element.
      • first

        public K first()
        Description copied from interface: PriorityQueue
        Returns the first element of the queue.
        Specified by:
        first in interface PriorityQueue<K>
        Returns:
        the first element.
      • size

        public int size()
        Description copied from interface: PriorityQueue
        Returns the number of elements in this queue.
        Specified by:
        size in interface PriorityQueue<K>
        Returns:
        the number of elements in this queue.
      • clear

        public void clear()
        Description copied from interface: PriorityQueue
        Removes all elements from this queue.
        Specified by:
        clear in interface PriorityQueue<K>
      • trim

        public void trim()
        Trims the underlying array so that it has exactly size() elements.
      • comparator

        public Comparator<? super K> comparator()
        Description copied from interface: PriorityQueue
        Returns the comparator associated with this queue, or null if it uses its elements' natural ordering.
        Specified by:
        comparator in interface PriorityQueue<K>
        Returns:
        the comparator associated with this sorted set, or null if it uses its elements' natural ordering.