001/* Copyright (C) 2013 TU Dortmund
002 * This file is part of AutomataLib, http://www.automatalib.net/.
003 * 
004 * AutomataLib is free software; you can redistribute it and/or
005 * modify it under the terms of the GNU Lesser General Public
006 * License version 3.0 as published by the Free Software Foundation.
007 * 
008 * AutomataLib is distributed in the hope that it will be useful,
009 * but WITHOUT ANY WARRANTY; without even the implied warranty of
010 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
011 * Lesser General Public License for more details.
012 * 
013 * You should have received a copy of the GNU Lesser General Public
014 * License along with AutomataLib; if not, see
015 * http://www.gnu.de/documents/lgpl.en.html.
016 */
017package net.automatalib.commons.smartcollections;
018
019
020/**
021 * Priority queue interface. Note that this class deliberately does not
022 * specify whether the inserted elements come with their own key (i.e.
023 * implement {@link Comparable} or can be compared using a comparator),
024 * or have external keys attached.
025 * 
026 * @author Malte Isberner <malte.isberner@gmail.com>
027 *
028 * @param <E> element class
029 */
030public interface SmartPriorityQueue<E> extends SmartCollection<E> {
031
032        /**
033         * Retrieves, but does not remove the element with the minimum key
034         * in the priority queue. If there are several elements with minimal key
035         * values, one of them is chosen arbitrarily.
036         * @return an element with a minimal key.
037         */
038        public abstract E peekMin();
039
040        /**
041         * Retrieves and remove the element with the minimum key in the priority
042         * queue. If there are several elements with minimal key values, one of
043         * them is chosen arbitrarily.
044         * @return the element with the previously minimal key.
045         */
046        public abstract E extractMin();
047
048}