6 public class GraphNode {
8 public static boolean useEdgeLabels;
10 /* NodeStatus enumeration pattern ***********/
12 public static final NodeStatus UNVISITED = new NodeStatus("UNVISITED");
13 public static final NodeStatus PROCESSING = new NodeStatus("PROCESSING");
14 public static final NodeStatus FINISHED = new NodeStatus("FINISHED");
16 public static class NodeStatus {
17 private static String name;
18 private NodeStatus(String name) { this.name = name; }
19 public String toString() { return name; }
22 /* Edge *****************/
24 public static class Edge {
27 private GraphNode target;
28 private String dotnodeparams = new String();
30 public Edge(String label, GraphNode target) {
35 public String getLabel() {
39 public GraphNode getTarget() {
43 public void setDotNodeParameters(String param) {
45 throw new NullPointerException();
47 if (param.length() > 0) {
48 dotnodeparams = "," + param;
50 dotnodeparams = new String();
56 int discoverytime = -1;
57 int finishingtime = -1; /* used for searches */
58 Vector edges = new Vector();
61 NodeStatus status = UNVISITED;
62 String dotnodeparams = new String();
65 public GraphNode(String label) {
66 this.nodelabel = label;
67 this.textlabel = label;
70 public GraphNode(String label, Object owner) {
71 this.nodelabel = label;
72 this.textlabel = label;
76 public GraphNode(String label, String textlabel, Object owner) {
77 this.nodelabel = label;
78 this.textlabel = textlabel;
82 public Object getOwner() {
86 public static void computeclosure(Set nodes) {
87 Stack tovisit=new Stack();
88 tovisit.addAll(nodes);
89 while(!tovisit.isEmpty()) {
90 GraphNode gn=(GraphNode)tovisit.pop();
91 for(Iterator it=gn.edges();it.hasNext();) {
92 Edge edge=(Edge)it.next();
93 GraphNode target=edge.getTarget();
94 if (!nodes.contains(target)) {
102 public void setDotNodeParameters(String param) {
104 throw new NullPointerException();
106 if (param.length() > 0) {
107 dotnodeparams = "," + param;
109 dotnodeparams = new String();
113 public void setStatus(NodeStatus status) {
114 if (status == null) {
115 throw new NullPointerException();
117 this.status = status;
120 public String getLabel() {
124 public String getTextLabel() {
128 public NodeStatus getStatus() {
132 public Iterator edges() {
133 return edges.iterator();
136 public void addEdge(Edge newedge) {
137 edges.addElement(newedge);
140 public void reset() {
146 public void discover(int time) {
147 discoverytime = time;
151 public void finish(int time) {
152 assert status == PROCESSING;
153 finishingtime = time;
157 public int getFinishingTime() {
158 return finishingtime;
162 public static class DOTVisitor {
164 java.io.PrintWriter output;
168 private DOTVisitor(java.io.OutputStream output) {
171 this.output = new java.io.PrintWriter(output, true);
174 private String getNewID(String name) {
175 tokennumber = tokennumber + 1;
176 return new String (name+tokennumber);
181 public static void visit(java.io.OutputStream output, Collection nodes) {
182 DOTVisitor visitor = new DOTVisitor(output);
183 visitor.nodes = nodes;
188 private void make() {
189 output.println("digraph dotvisitor {");
190 output.println("\trotate=90;");
191 /* output.println("\tpage=\"8.5,11\";");
192 output.println("\tnslimit=1000.0;");
193 output.println("\tnslimit1=1000.0;");
194 output.println("\tmclimit=1000.0;");
195 output.println("\tremincross=true;");*/
196 output.println("\tnode [fontsize=10,height=\"0.1\", width=\"0.1\"];");
197 output.println("\tedge [fontsize=6];");
199 output.println("}\n");
202 private void traverse() {
203 Set cycleset=GraphNode.findcycles(nodes);
205 Iterator i = nodes.iterator();
206 while (i.hasNext()) {
207 GraphNode gn = (GraphNode) i.next();
208 Iterator edges = gn.edges();
209 String label = gn.getTextLabel(); // + " [" + gn.discoverytime + "," + gn.finishingtime + "];";
211 if (cycleset.contains(gn))
212 option=",style=bold";
213 output.println("\t" + gn.getLabel() + " [label=\"" + label + "\"" + gn.dotnodeparams + option+"];");
215 while (edges.hasNext()) {
216 Edge edge = (Edge) edges.next();
217 GraphNode node = edge.getTarget();
218 if (nodes.contains(node)) {
219 String edgelabel = useEdgeLabels ? "label=\"" + edge.getLabel() + "\"" : "label=\"\"";
220 output.println("\t" + gn.getLabel() + " -> " + node.getLabel() + " [" + edgelabel + edge.dotnodeparams + "];");
227 /* XXXXXXXX Should use SCC algorithm here - will change */
228 public static Set findcycles(Collection nodes) {
229 Stack st=new Stack();
230 HashSet acyclic=new HashSet();
231 HashSet cycles=new HashSet();
232 for(Iterator it=nodes.iterator();it.hasNext();) {
233 GraphNode node=(GraphNode)it.next();
234 if (acyclic.contains(node))
236 if (cycles.contains(node))
238 findcycles(cycles, acyclic, st,node,nodes);
243 private static boolean findcycles(Set cycles, Set acyclic, Stack visited, GraphNode gn, Collection nodes) {
244 if (visited.contains(gn)) {/* Found cycle */
245 cycles.addAll(visited.subList(visited.indexOf(gn),visited.size())); /* Add this cycle */
248 boolean acyclicflag=true;
250 for(Iterator it=gn.edges();it.hasNext();) {
251 Edge e=(Edge) it.next();
252 GraphNode node = e.getTarget();
253 if (!nodes.contains(node))
254 continue; /* Don't visit stuff outside set */
255 if (acyclic.contains(node))
257 if (findcycles(cycles,acyclic,visited,node,nodes)) {
264 acyclic.add(gn); /* no cycles through gn */
267 return true; /* found cycle */
271 * DFS encapsulates the depth first search algorithm
273 public static class DFS {
278 private DFS(Collection nodes) {
282 public static boolean depthFirstSearch(Collection nodes) {
284 throw new NullPointerException();
287 DFS dfs = new DFS(nodes);
291 private boolean go() {
294 boolean acyclic=true;
295 i = nodes.iterator();
296 while (i.hasNext()) {
297 GraphNode gn = (GraphNode) i.next();
301 i = nodes.iterator();
302 while (i.hasNext()) {
303 GraphNode gn = (GraphNode) i.next();
304 assert gn.getStatus() != PROCESSING;
305 if (gn.getStatus() == UNVISITED) {
313 private boolean dfs(GraphNode gn) {
314 boolean acyclic=true;
316 Iterator edges = gn.edges();
318 while (edges.hasNext()) {
319 Edge edge = (Edge) edges.next();
320 GraphNode node = edge.getTarget();
321 if (node.getStatus() == UNVISITED) {
324 } else if (node.getStatus()==PROCESSING) {