001/*
002 * Copyright 2006 - 2013
003 *     Stefan Balev     <stefan.balev@graphstream-project.org>
004 *     Julien Baudry    <julien.baudry@graphstream-project.org>
005 *     Antoine Dutot    <antoine.dutot@graphstream-project.org>
006 *     Yoann Pigné      <yoann.pigne@graphstream-project.org>
007 *     Guilhelm Savin   <guilhelm.savin@graphstream-project.org>
008 * 
009 * This file is part of GraphStream <http://graphstream-project.org>.
010 * 
011 * GraphStream is a library whose purpose is to handle static or dynamic
012 * graph, create them from scratch, file or any source and display them.
013 * 
014 * This program is free software distributed under the terms of two licenses, the
015 * CeCILL-C license that fits European law, and the GNU Lesser General Public
016 * License. You can  use, modify and/ or redistribute the software under the terms
017 * of the CeCILL-C license as circulated by CEA, CNRS and INRIA at the following
018 * URL <http://www.cecill.info> or under the terms of the GNU LGPL as published by
019 * the Free Software Foundation, either version 3 of the License, or (at your
020 * option) any later version.
021 * 
022 * This program is distributed in the hope that it will be useful, but WITHOUT ANY
023 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
024 * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
025 * 
026 * You should have received a copy of the GNU Lesser General Public License
027 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
028 * 
029 * The fact that you are presently reading this means that you have had
030 * knowledge of the CeCILL-C and LGPL licenses and that you accept their terms.
031 */
032package org.graphstream.algorithm;
033
034import java.util.Iterator;
035
036import org.graphstream.graph.Edge;
037import org.graphstream.graph.Graph;
038
039/**
040 * This interface defines the basic functionalities of a spanning tree algorithm.
041 * 
042 * <p> It defines methods related to tagging the edges of the spanning tree and for iterating on them.</p>
043 */
044public interface SpanningTree extends Algorithm {
045        /**
046         * Get key attribute which will be used to set if edges are in the spanning
047         * tree, or not.
048         * 
049         * @return flag attribute
050         */
051        String getFlagAttribute();
052        
053        /**
054         * Set the flag attribute.
055         * 
056         * @param flagAttribute
057         *            New attribute used. If {@code null} edges are not tagged.
058         * @throws IllegalStateException
059         *             if {@link #init(Graph)} is already called
060         */
061        void setFlagAttribute(String flagAttribute);
062        
063        /**
064         * Get value used to set that an edge is in the spanning tree.
065         * 
066         * @return on value
067         */
068        Object getFlagOn();
069        
070        /**
071         * Set value used to set that an edge is in the spanning tree.
072         * 
073         * @param flagOn
074         *            on value. If {@code null} edges in the tree are not tagged.
075         * @throws IllegalStateException
076         *             if {@link #init(Graph)} is already called
077         */
078        void setFlagOn(Object flagOn);
079        
080        /**
081         * Get value used to set that an edge is not in the spanning tree.
082         * 
083         * @return off value
084         */
085        Object getFlagOff();
086        
087        
088        /**
089         * Set value used to set that an edge is not in the spanning tree.
090         * 
091         * @param newFlagOff
092         *            off value. If {@code null} edges out of the tree are not
093         *            tagged.
094         * @throws IllegalStateException
095         *             if {@link #init(Graph)} is already called
096         */
097        void setFlagOff(Object flagOff);
098        
099        /**
100         * Removes the tags of all edges. Use this method to save memory if the
101         * spanning tree is used no more.
102         */
103        void clear();
104
105        /**
106         * An iterator on the tree edges.
107         * 
108         * @return An iterator on the tree edges
109         */
110        <T extends Edge> Iterator<T> getTreeEdgesIterator();
111        
112        
113        /**
114         * Iterable view of the spanning tree edges. This implementation uses
115         * {@link #getTreeEdgesIterator()}.
116         * 
117         * @return Iterable view of the tree edges.
118         */
119        <T extends Edge> Iterable<T> getTreeEdges();
120}