Programming Languages Research Group: Git - IRC.git/blob

   1 package Util;
   2
   3 import java.util.*;
   4 import java.io.*;
   5
   6 public class GraphNode {
   7     /* NodeStatus enumeration pattern ***********/
   8
   9     public static final NodeStatus UNVISITED = new NodeStatus("UNVISITED");
  10     public static final NodeStatus PROCESSING = new NodeStatus("PROCESSING");
  11     public static final NodeStatus FINISHED = new NodeStatus("FINISHED");
  12
  13     public static class NodeStatus {
  14         private static String name;
  15         private NodeStatus(String name) { this.name = name; }
  16         public String toString() { return name; }
  17     }
  18
  19     int discoverytime = -1;
  20     int finishingtime = -1; /* used for searches */
  21
  22     protected Vector edges = new Vector();
  23     protected Vector inedges = new Vector();
  24
  25     NodeStatus status = UNVISITED;
  26     String dotnodeparams = new String();
  27     public boolean merge=false;
  28
  29     public void setMerge() {
  30         merge=true;
  31     }
  32
  33     public static void computeclosure(Collection nodes, Collection removed) {
  34         Stack tovisit=new Stack();
  35         tovisit.addAll(nodes);
  36         while(!tovisit.isEmpty()) {
  37             GraphNode gn=(GraphNode)tovisit.pop();
  38             for(Iterator it=gn.edges();it.hasNext();) {
  39                 Edge edge=(Edge)it.next();
  40                 GraphNode target=edge.getTarget();
  41                 if (!nodes.contains(target)) {
  42                     if ((removed==null)||
  43                         (!removed.contains(target))) {
  44                         nodes.add(target);
  45                         tovisit.push(target);
  46                     }
  47                 }
  48             }
  49         }
  50     }
  51
  52     public static void boundedcomputeclosure(Collection nodes, Collection removed,int depth) {
  53         Stack tovisit=new Stack();
  54         Stack newvisit=new Stack();
  55         tovisit.addAll(nodes);
  56         for(int i=0;i<depth&&!tovisit.isEmpty();i++) {
  57             while(!tovisit.isEmpty()) {
  58                 GraphNode gn=(GraphNode)tovisit.pop();
  59                 for(Iterator it=gn.edges();it.hasNext();) {
  60                     Edge edge=(Edge)it.next();
  61                     GraphNode target=edge.getTarget();
  62                     if (!nodes.contains(target)) {
  63                         if ((removed==null)||
  64                             (!removed.contains(target))) {
  65                             nodes.add(target);
  66                             newvisit.push(target);
  67                         }
  68                     }
  69                 }
  70             }
  71             tovisit=newvisit;
  72             newvisit=new Stack();
  73         }
  74     }
  75
  76     public void setDotNodeParameters(String param) {
  77         if (param == null) {
  78             throw new NullPointerException();
  79         }
  80         if (dotnodeparams.length() > 0) {
  81             dotnodeparams += "," + param;
  82         } else {
  83             dotnodeparams = param;
  84         }
  85     }
  86
  87     public void setStatus(NodeStatus status) {
  88         if (status == null) {
  89             throw new NullPointerException();
  90         }
  91         this.status = status;
  92     }
  93
  94     public String getLabel() {
  95         return "";
  96     }
  97
  98     public String getTextLabel() {
  99         return "";
 100     }
 101
 102         public String getName(){
 103                 return "";
 104         }
 105
 106     public NodeStatus getStatus() {
 107         return this.status;
 108     }
 109
 110     public int numedges() {
 111         return edges.size();
 112     }
 113
 114     public int numinedges() {
 115         return inedges.size();
 116     }
 117
 118     public Edge getedge(int i) {
 119         return (Edge) edges.get(i);
 120     }
 121
 122     public Edge getinedge(int i) {
 123         return (Edge) inedges.get(i);
 124     }
 125
 126     public Vector getEdgeVector() {
 127         return edges;
 128     }
 129
 130     public Vector getInedgeVector() {
 131         return inedges;
 132     }
 133
 134     public Iterator edges() {
 135         return edges.iterator();
 136     }
 137
 138     public Iterator inedges() {
 139         return inedges.iterator();
 140     }
 141
 142     public void addEdge(Edge newedge) {
 143         newedge.setSource(this);
 144         edges.addElement(newedge);
 145         GraphNode tonode=newedge.getTarget();
 146         tonode.inedges.addElement(newedge);
 147     }
 148
 149     public void addEdge(Vector v) {
 150         for (Iterator it = v.iterator(); it.hasNext();)
 151             addEdge((Edge)it.next());
 152     }
 153
 154     public void removeEdge(Edge edge) {
 155         edges.remove(edge);
 156     }
 157
 158     public void removeInedge(Edge edge) {
 159         inedges.remove(edge);
 160     }
 161
 162     public void removeAllEdges() {
 163         edges.removeAllElements();
 164     }
 165
 166     public void removeAllInedges() {
 167         inedges.removeAllElements();
 168     }
 169     void reset() {
 170             discoverytime = -1;
 171             finishingtime = -1;
 172             status = UNVISITED;
 173     }
 174
 175     void resetscc() {
 176         status = UNVISITED;
 177     }
 178
 179     void discover(int time) {
 180         discoverytime = time;
 181         status = PROCESSING;
 182     }
 183
 184     void finish(int time) {
 185         assert status == PROCESSING;
 186         finishingtime = time;
 187         status = FINISHED;
 188     }
 189
 190     /** Returns finishing time for dfs */
 191
 192     public int getFinishingTime() {
 193         return finishingtime;
 194     }
 195
 196
 197     public static class DOTVisitor {
 198
 199         java.io.PrintWriter output;
 200         int tokennumber;
 201         int color;
 202         Vector namers;
 203
 204         private DOTVisitor(java.io.OutputStream output, Vector namers) {
 205             tokennumber = 0;
 206             color = 0;
 207             this.output = new java.io.PrintWriter(output, true);
 208             this.namers=namers;
 209         }
 210
 211         private String getNewID(String name) {
 212             tokennumber = tokennumber + 1;
 213             return new String (name+tokennumber);
 214         }
 215
 216         Collection nodes;
 217
 218
 219         public static void visit(java.io.OutputStream output, Collection nodes, Vector namers) {
 220             DOTVisitor visitor = new DOTVisitor(output, namers);
 221             visitor.nodes = nodes;
 222             visitor.make();
 223         }
 224
 225         public static void visit(java.io.OutputStream output, Collection nodes) {
 226             Vector v=new Vector();
 227             v.add(new Namer());
 228             DOTVisitor visitor = new DOTVisitor(output, v);
 229             visitor.nodes = nodes;
 230             visitor.make();
 231         }
 232
 233         private void make() {
 234             output.println("digraph dotvisitor {");
 235             /*            output.println("\tpage=\"8.5,11\";");
 236                           output.println("\tnslimit=1000.0;");
 237                           output.println("\tnslimit1=1000.0;");
 238                           output.println("\tmclimit=1000.0;");
 239                           output.println("\tremincross=true;");*/
 240             output.println("\tnode [fontsize=10,height=\"0.1\", width=\"0.1\"];");
 241             output.println("\tedge [fontsize=6];");
 242             traverse();
 243             output.println("}\n");
 244         }
 245
 246
 247
 248         private void traverse() {
 249             Set cycleset=GraphNode.findcycles(nodes);
 250
 251             Iterator it = nodes.iterator();
 252             while (it.hasNext()) {
 253                 GraphNode gn = (GraphNode) it.next();
 254                 Iterator edges = gn.edges();
 255                 String label = "";
 256                 String dotnodeparams="";
 257
 258                 for(int i=0;i<namers.size();i++) {
 259                     Namer name=(Namer) namers.get(i);
 260                     String newlabel=name.nodeLabel(gn);
 261                     String newparams=name.nodeOption(gn);
 262
 263                     if (!newlabel.equals("") && !label.equals("")) {
 264                         label+=", ";
 265                     }
 266                     if (!newparams.equals("")) {
 267                         dotnodeparams+=", " + name.nodeOption(gn);
 268                     }
 269                     label+=name.nodeLabel(gn);
 270                 }
 271
 272                 if (!gn.merge)
 273                     output.println("\t" + gn.getLabel() + " [label=\"" + label + "\"" + dotnodeparams + "];");
 274
 275                 if (!gn.merge)
 276                 while (edges.hasNext()) {
 277                     Edge edge = (Edge) edges.next();
 278                     GraphNode node = edge.getTarget();
 279                     if (nodes.contains(node)) {
 280                         for(Iterator nodeit=nonmerge(node).iterator();nodeit.hasNext();) {
 281                             GraphNode node2=(GraphNode)nodeit.next();
 282                             String edgelabel = "";
 283                             String edgedotnodeparams="";
 284
 285                             for(int i=0;i<namers.size();i++) {
 286                                 Namer name=(Namer) namers.get(i);
 287                                 String newlabel=name.edgeLabel(edge);
 288                                 String newoption=name.edgeOption(edge);
 289                                 if (!newlabel.equals("")&& ! edgelabel.equals(""))
 290                                     edgelabel+=", ";
 291                                 edgelabel+=newlabel;
 292                                 if (!newoption.equals(""))
 293                                     edgedotnodeparams+=", "+newoption;
 294                             }
 295
 296                             output.println("\t" + gn.getLabel() + " -> " + node2.getLabel() + " [" + "label=\"" + edgelabel + "\"" + edgedotnodeparams + "];");
 297                         }
 298                     }
 299                 }
 300             }
 301         }
 302
 303         Set nonmerge(GraphNode gn) {
 304             HashSet newset=new HashSet();
 305             HashSet toprocess=new HashSet();
 306             toprocess.add(gn);
 307             while(!toprocess.isEmpty()) {
 308                 GraphNode gn2=(GraphNode)toprocess.iterator().next();
 309                 toprocess.remove(gn2);
 310                 if (!gn2.merge)
 311                     newset.add(gn2);
 312                 else {
 313                     Iterator edges = gn2.edges();
 314                     while (edges.hasNext()) {
 315                         Edge edge = (Edge) edges.next();
 316                         GraphNode node = edge.getTarget();
 317                         if (!newset.contains(node)&&nodes.contains(node))
 318                             toprocess.add(node);
 319                     }
 320                 }
 321             }
 322             return newset;
 323         }
 324
 325     }
 326
 327     /** This function returns the set of nodes involved in cycles.
 328      *  It only considers cycles containing nodes in the set 'nodes'.
 329     */
 330     public static Set findcycles(Collection nodes) {
 331         HashSet cycleset=new HashSet();
 332         SCC scc=DFS.computeSCC(nodes);
 333         if (!scc.hasCycles())
 334             return cycleset;
 335         for(int i=0;i<scc.numSCC();i++) {
 336             if (scc.hasCycle(i))
 337                 cycleset.addAll(scc.getSCC(i));
 338         }
 339         return cycleset;
 340     }
 341
 342     public static class SCC {
 343         boolean acyclic;
 344         HashMap map,revmap;
 345         int numscc;
 346         public SCC(boolean acyclic, HashMap map,HashMap revmap,int numscc) {
 347             this.acyclic=acyclic;
 348             this.map=map;
 349             this.revmap=revmap;
 350             this.numscc=numscc;
 351         }
 352
 353         /** Returns whether the graph has any cycles */
 354         public boolean hasCycles() {
 355             return !acyclic;
 356         }
 357
 358         /** Returns the number of Strongly Connected Components */
 359         public int numSCC() {
 360             return numscc;
 361         }
 362
 363         /** Returns the strongly connected component number for the GraphNode gn*/
 364         public int getComponent(GraphNode gn) {
 365             return ((Integer)revmap.get(gn)).intValue();
 366         }
 367
 368         /** Returns the set of nodes in the strongly connected component i*/
 369         public Set getSCC(int i) {
 370             Integer scc=new Integer(i);
 371             return (Set)map.get(scc);
 372         }
 373
 374         /** Returns whether the strongly connected component i contains a cycle */
 375         boolean hasCycle(int i) {
 376             Integer scc=new Integer(i);
 377             Set s=(Set)map.get(scc);
 378             if (s.size()>1)
 379                 return true;
 380             Object [] array=s.toArray();
 381             GraphNode gn=(GraphNode)array[0];
 382             for(Iterator it=gn.edges();it.hasNext();) {
 383                 Edge e=(Edge)it.next();
 384                 if (e.getTarget()==gn)
 385                     return true; /* Self Cycle */
 386             }
 387             return false;
 388         }
 389     }
 390
 391     /**
 392      * DFS encapsulates the depth first search algorithm
 393      */
 394     public static class DFS {
 395
 396         int time = 0;
 397         int sccindex = 0;
 398         Collection nodes;
 399         Vector finishingorder=null;
 400         HashMap sccmap;
 401         HashMap sccmaprev;
 402
 403         private DFS(Collection nodes) {
 404             this.nodes = nodes;
 405         }
 406         /** Calculates the strong connected components for the graph composed
 407          *  of the set of nodes 'nodes'*/
 408         public static SCC computeSCC(Collection nodes) {
 409             if (nodes==null) {
 410                 throw new NullPointerException();
 411             }
 412             DFS dfs=new DFS(nodes);
 413             dfs.sccmap=new HashMap();
 414             dfs.sccmaprev=new HashMap();
 415             dfs.finishingorder=new Vector();
 416             boolean acyclic=dfs.go();
 417             for (Iterator it = nodes.iterator();it.hasNext();) {
 418                 GraphNode gn = (GraphNode) it.next();
 419                 gn.resetscc();
 420             }
 421             for(int i=dfs.finishingorder.size()-1;i>=0;i--) {
 422                 GraphNode gn=(GraphNode)dfs.finishingorder.get(i);
 423                 if (gn.getStatus() == UNVISITED) {
 424                     dfs.dfsprev(gn);
 425                     dfs.sccindex++; /* Increment scc index */
 426                 }
 427             }
 428             return new SCC(acyclic,dfs.sccmap,dfs.sccmaprev,dfs.sccindex);
 429         }
 430
 431         void dfsprev(GraphNode gn) {
 432             if (gn.getStatus()==FINISHED||!nodes.contains(gn))
 433                 return;
 434             gn.setStatus(FINISHED);
 435             Integer i=new Integer(sccindex);
 436             if (!sccmap.containsKey(i))
 437                 sccmap.put(i,new HashSet());
 438             ((Set)sccmap.get(i)).add(gn);
 439             sccmaprev.put(gn,i);
 440             for(Iterator edgeit=gn.inedges();edgeit.hasNext();) {
 441                 Edge e=(Edge)edgeit.next();
 442                 GraphNode gn2=e.getSource();
 443                 dfsprev(gn2);
 444             }
 445         }
 446
 447         public static boolean depthFirstSearch(Collection nodes) {
 448             if (nodes == null) {
 449                 throw new NullPointerException();
 450             }
 451
 452             DFS dfs = new DFS(nodes);
 453             return dfs.go();
 454         }
 455
 456         private boolean go() {
 457             Iterator i;
 458             time = 0;
 459             boolean acyclic=true;
 460             i = nodes.iterator();
 461             while (i.hasNext()) {
 462                 GraphNode gn = (GraphNode) i.next();
 463                 gn.reset();
 464             }
 465
 466             i = nodes.iterator();
 467             while (i.hasNext()) {
 468                 GraphNode gn = (GraphNode) i.next();
 469                 assert gn.getStatus() != PROCESSING;
 470                 if (gn.getStatus() == UNVISITED) {
 471                     if (!dfs(gn))
 472                         acyclic=false;
 473                 }
 474             }
 475             return acyclic;
 476         }
 477
 478         private boolean dfs(GraphNode gn) {
 479             boolean acyclic=true;
 480             gn.discover(time++);
 481             Iterator edges = gn.edges();
 482
 483             while (edges.hasNext()) {
 484                 Edge edge = (Edge) edges.next();
 485                 GraphNode node = edge.getTarget();
 486                 if (!nodes.contains(node)) /* Skip nodes which aren't in the set */
 487                     continue;
 488                 if (node.getStatus() == UNVISITED) {
 489                     if (!dfs(node))
 490                         acyclic=false;
 491                 } else if (node.getStatus()==PROCESSING) {
 492                     acyclic=false;
 493                 }
 494             }
 495             if (finishingorder!=null)
 496                 finishingorder.add(gn);
 497             gn.finish(time++);
 498             return acyclic;
 499         }
 500
 501     } /* end DFS */
 502
 503 }