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.graph.implementations;
033
034import java.util.Collections;
035import java.util.HashMap;
036import java.util.Iterator;
037
038import org.graphstream.graph.Edge;
039import org.graphstream.graph.Node;
040
041/**
042 * Nodes used with {@link SingleGraph}
043 *
044 */
045
046public class SingleNode extends AdjacencyListNode {
047        protected static class TwoEdges {
048                AbstractEdge in, out;
049        }
050        
051        protected HashMap<AbstractNode, TwoEdges> neighborMap;
052
053        // *** Constructor ***
054
055        protected SingleNode(AbstractGraph graph, String id) {
056                super(graph, id);
057                neighborMap = new HashMap<AbstractNode, TwoEdges>(
058                                4 * INITIAL_EDGE_CAPACITY / 3 + 1);
059        }
060
061        // *** Helpers ***
062
063        @SuppressWarnings("unchecked")
064        @Override
065        protected <T extends Edge> T locateEdge(Node opposite, char type) {
066                TwoEdges ee = neighborMap.get(opposite);
067                if (ee == null)
068                        return null;
069                return (T)(type == I_EDGE ? ee.in : ee.out);
070        }
071
072        @Override
073        protected void removeEdge(int i) {
074                AbstractNode opposite = edges[i].getOpposite(this);
075                TwoEdges ee = neighborMap.get(opposite);
076                char type = edgeType(edges[i]);
077                if (type != O_EDGE)
078                        ee.in = null;
079                if (type != I_EDGE)
080                        ee.out = null;
081                if (ee.in == null && ee.out == null)
082                        neighborMap.remove(opposite);
083                super.removeEdge(i);
084        }
085
086        // *** Callbacks ***
087
088        @Override
089        protected boolean addEdgeCallback(AbstractEdge edge) {
090                AbstractNode opposite = edge.getOpposite(this);
091                TwoEdges ee = neighborMap.get(opposite);
092                if (ee == null)
093                        ee = new TwoEdges();
094                char type = edgeType(edge);
095                if (type != O_EDGE) {
096                        if (ee.in != null)
097                                return false;
098                        ee.in = edge;
099                }
100                if (type != I_EDGE) {
101                        if (ee.out != null)
102                                return false;
103                        ee.out = edge;
104                }
105                neighborMap.put(opposite, ee);
106                return super.addEdgeCallback(edge);
107        }
108
109        @Override
110        protected void clearCallback() {
111                neighborMap.clear();
112                super.clearCallback();
113        }
114
115        // *** Others ***
116
117        @SuppressWarnings("unchecked")
118        @Override
119        public <T extends Node> Iterator<T> getNeighborNodeIterator() {
120                return (Iterator<T>) Collections.unmodifiableSet(neighborMap.keySet())
121                                .iterator();
122        }
123}