nz.ac.waikato.jdsl.core.api
Interface PriorityQueue

All Superinterfaces:

Container, InspectableContainer, InspectableKeyBasedContainer, KeyBasedContainer

All Known Implementing Classes:

ArrayHeap

public interface PriorityQueue
extends KeyBasedContainer

A partially-ordered container that allows for removal of the element with highest priority. The names of the methods (e.g., min()) assume that high priorities are numerically low, but nothing except the names requires this convention.

The interface makes no assumptions about how comparisons are made, or how the elements are ordered. The priority of two elements may be hardcoded or chosen dynamicaly, depending upon the specific implementation.

Note that there is no InspectablePriorityQueue.

Version:

JDSL 2.1.1

Author:

Mark Handy, Andrew Schwerin, Luca Vismara

Method Summary

Locator	min() Allows access to element with highest priority without removing it from the priority queue.
java.lang.Object	removeMin() Pops the highest-priority element off the priority queue and updates the priority queue.

Methods inherited from interface nz.ac.waikato.jdsl.core.api.KeyBasedContainer

insert, remove, replaceKey

Methods inherited from interface nz.ac.waikato.jdsl.core.api.InspectableKeyBasedContainer

keys, locators

Methods inherited from interface nz.ac.waikato.jdsl.core.api.Container

newContainer, replaceElement

Methods inherited from interface nz.ac.waikato.jdsl.core.api.InspectableContainer

contains, elements, isEmpty, size

Method Detail

min

Locator min()
            throws EmptyContainerException

Allows access to element with highest priority without removing it from the priority queue.

Returns:

the locator to the element with highest priority in the priority queue

Throws:

EmptyContainerException - if the priority queue is empty

removeMin

java.lang.Object removeMin()
                           throws EmptyContainerException

Pops the highest-priority element off the priority queue and updates the priority queue.

Returns:

an element with highest priority in the priority queue

Throws:

EmptyContainerException - if the priority queue is empty