PriorityQueue


1   /*
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49  */
50  package org.apache.avalon.excalibur.collections;
51  
52  import java.util.NoSuchElementException  ;
53  
54  /**
55   * Iterface for priority queues.
56   * This interface does not dictate whether it is min or max heap.
57   *
58   * @deprecated use org.apache.commons.collections.PriorityQueue instead
59   *
60   * @author <a HREF="mailto:peter@apache.org">Peter Donald</a>
61   * @version CVS $Revision: 1.4 $ $Date: 2003/03/22 12:46:22 $
62   * @since 4.0
63   */
64  public interface PriorityQueue
65  {
66      /**
67       * Clear all elements from queue.
68       */
69      void clear();
70  
71      /**
72       * Test if queue is empty.
73       *
74       * @return true if queue is empty else false.
75       */
76      boolean isEmpty();
77  
78      /**
79       * Insert an element into queue.
80       *
81       * @param element the element to be inserted
82       */
83      void insert( Object   element );
84  
85      /**
86       * Return element on top of heap but don't remove it.
87       *
88       * @return the element at top of heap
89       * @throws NoSuchElementException if isEmpty() == true
90       */
91      Object   peek() throws NoSuchElementException  ;
92  
93      /**
94       * Return element on top of heap and remove it.
95       *
96       * @return the element at top of heap
97       * @throws NoSuchElementException if isEmpty() == true
98       */
99      Object   pop() throws NoSuchElementException  ;
100 }
101 
102
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