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.stream.file; 033 034import java.io.IOException; 035import java.io.InputStream; 036import java.io.Reader; 037import java.net.URL; 038import java.util.HashSet; 039 040/** 041 * Reader for the "LGL" graph format. 042 * 043 * <p> 044 * The LGL graph format is a simple format where each line beginning by a 045 * sharp sign "#" describes a source vertex, and each subsequent line 046 * not beginning by a sharp sign describe an edge target for this source. 047 * </p> 048 * 049 * <p> 050 * Also, the format does not specify any direction for edges. By default all 051 * edges are undirected. 052 * </p> 053 * 054 * <p> 055 * This format only contains edges. To ensure the "add node" events are sent 056 * before an edge referencing two nodes is created via an "add edge" event, this 057 * reader has a hash set of already encountered nodes. The hash set allows to 058 * issue "add node" events only when a node is encountered for the first time. 059 * </p> 060 * 061 * </p> This hash set consumes memory, but is the only way to ensure "add node" 062 * events are correctly issued. If this input is directly connected to a graph, 063 * as graphs can create non-existing nodes automatically, you can disable the 064 * hash set of nodes using the constructor 065 * {@link #FileSourceLGL(boolean)}, and giving "false" for the first 066 * argument. </p> 067 * 068 * The usual file name extension for this format is ".lgl". 069 */ 070public class FileSourceLGL extends FileSourceBase { 071 // Attribute 072 073 /** 074 * Allocator for edge identifiers. 075 */ 076 protected int edgeid = 0; 077 078 /** 079 * Set of existing nodes (if nodes are declared). 080 */ 081 protected HashSet<String> nodes; 082 083 /** 084 * The current source node. 085 */ 086 protected String source; 087 088 protected String graphName = "LGL_"; 089 090 // Construction 091 092 /** 093 * New reader for the "LGL" format. 094 */ 095 public FileSourceLGL() { 096 this(false); 097 } 098 099 /** 100 * New reader for the "LGL" format. 101 * 102 * @param declareNodes 103 * If true (default=true) this reader outputs nodeAdded events. 104 */ 105 public FileSourceLGL(boolean declareNodes) { 106 nodes = declareNodes ? new HashSet<String>() : null; 107 } 108 109 // Commands 110 111 @Override 112 protected void continueParsingInInclude() throws IOException { 113 // Should not happen, NCol files cannot be nested. 114 } 115 116 @Override 117 public boolean nextEvents() throws IOException { 118 String id1 = getWordOrSymbolOrNumberOrStringOrEolOrEof(); 119 120 if (id1.equals("EOL")) { 121 // Empty line. Skip it. 122 } else if (id1.equals("EOF")) { 123 return false; 124 } else if (id1.equals("#")) { 125 // A new sequence of edges starts 126 String src = getWordOrNumberOrStringOrEolOrEof(); 127 128 if(!src.equals("EOL") && !src.equals("EOF")) { 129 source = src; 130 } else { 131 source = null; 132 } 133 } else { 134 // we got a new target. 135 if(source != null) { 136 String weight = getWordOrNumberOrStringOrEolOrEof(); 137 double w = 0.0; 138 139 if(weight.equals("EOL") || weight.equals("EOF")) { 140 weight = null; 141 pushBack(); 142 } else { 143 try { 144 w = Double.parseDouble(weight); 145 } catch(Exception e) { 146 throw new IOException(String.format("cannot transform weight %s into a number", weight)); 147 } 148 } 149 150 String edgeId = Integer.toString(edgeid++); 151 152 sendEdgeAdded(graphName, edgeId, source, id1, false); 153 154 if(weight != null) { 155 sendEdgeAttributeAdded(graphName, edgeId, "weight", (Double)w); 156 } 157 } 158 } 159 160 return true; 161 } 162 163 protected void declareNode(String id) { 164 if (nodes != null) { 165 if (!nodes.contains(id)) { 166 sendNodeAdded(graphName, id); 167 nodes.add(id); 168 } 169 } 170 } 171 172 @Override 173 public void begin(String filename) throws IOException { 174 super.begin(filename); 175 init(); 176 } 177 178 @Override 179 public void begin(URL url) throws IOException { 180 super.begin(url); 181 init(); 182 } 183 184 @Override 185 public void begin(InputStream stream) throws IOException { 186 super.begin(stream); 187 init(); 188 } 189 190 @Override 191 public void begin(Reader reader) throws IOException { 192 super.begin(reader); 193 init(); 194 } 195 196 protected void init() throws IOException { 197 st.eolIsSignificant(true); 198 st.commentChar('%'); 199 200 graphName = String.format("%s_%d", graphName, 201 System.currentTimeMillis() + ((long) Math.random() * 10)); 202 } 203 204 public boolean nextStep() throws IOException { 205 return nextEvents(); 206 } 207 208 @Override 209 public void end() throws IOException { 210 super.end(); 211 } 212}