org.apache.commons.collections

## Interface PriorityQueue

- All Known Implementing Classes:
    BinaryHeap, SynchronizedPriorityQueue

  Deprecated.
  Replaced by the Buffer interface and implementations in buffer subpackage. Due to be removed in v4.0.

      public interface PriorityQueue

  Defines a collection for priority queues, which can insert, peek and pop.

  This interface is now replaced by the `Buffer` interface.

  Since:
    Commons Collections 1.0
  Version:
    $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
  Author:
    Peter Donald

- - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `clear()` Deprecated. Clear all elements from queue.
    `void` | `insert(Object element)` Deprecated. Insert an element into queue.
    `boolean` | `isEmpty()` Deprecated. Test if queue is empty.
    `Object` | `peek()` Deprecated. Return element on top of heap but don't remove it.
    `Object` | `pop()` Deprecated. Return element on top of heap and remove it.

- - ### Method Detail

    - #### clear

          void clear()

      Deprecated.
      Clear all elements from queue.

    - #### isEmpty

          boolean isEmpty()

      Deprecated.
      Test if queue is empty.
      Returns:
        true if queue is empty else false.

    - #### insert

          void insert(Object element)

      Deprecated.
      Insert an element into queue.
      Parameters:
        `element` - the element to be inserted
      Throws:
        `ClassCastException` - if the specified `element`'s type prevents it from being compared to other items in the queue to determine its relative priority.

    - #### peek

          Object peek()

      Deprecated.
      Return element on top of heap but don't remove it.
      Returns:
        the element at top of heap
      Throws:
        `NoSuchElementException` - if `isEmpty() == true`

    - #### pop

          Object pop()

      Deprecated.
      Return element on top of heap and remove it.
      Returns:
        the element at top of heap
      Throws:
        `NoSuchElementException` - if `isEmpty() == true`

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