continuata implementazione di graph. bfs dfs kruskal dijkstra

graph/BFS.java

@@ -0,0 +1,131 @@
+
+//gioel
+
+package graph;
+
+
+import arraylist.ArrayIndexList;
+import arraylist.IndexList;
+import position.NodePositionList;
+import position.PositionList;
+
+import java.security.InvalidKeyException;
+
+public abstract class BFS<V, E, I, R> {
+    protected Graph<V, E> graph;
+    protected Vertex<V> start;
+    protected I info;
+    protected R visitResult;
+    protected static Object STATUS = new Object();
+    protected static Object VISITED = new Object();
+    protected static Object UNVISITED = new Object();
+
+    protected IndexList<PositionList<Vertex<V>>> layers;
+
+    public R execute(Graph<V, E> g, Vertex<V> s, I in) throws InvalidKeyException{
+	graph = g;
+	layers = new ArrayIndexList<PositionList<Vertex<V>>>(
+		graph.numVertices());
+	start = s;
+	info = in;
+	for (Vertex<V> v : graph.vertices())
+	    unVisit(v);
+	for (Edge<E> e : graph.edges())
+	    unVisit(e);
+
+	setup();
+	return finalResult(bfsTraversal(start));
+    }
+
+    protected void setup() {
+    }
+
+    protected R bfsTraversal(Vertex<V> v) throws InvalidKeyException{
+	initResult();
+	if (!isDone())
+	    startVisit(v);
+
+	if (!isDone()) {
+	    visit(v);
+
+	    layers.add(0, new NodePositionList<Vertex<V>>());
+	    layers.get(0).addLast(v);
+	}
+
+	int i = 0;
+	while (!layers.get(i).isEmpty())  {
+	    layers.add(i + 1, new NodePositionList<Vertex<V>>());
+
+	    for (Vertex<V> vertexInLayer : layers.get(i)) {
+		for (Edge<E> e : graph.incidentEdges(vertexInLayer)) {
+		    if (!isVisited(e)) {
+			visit(e);
+			Vertex<V> w = graph.opposite(vertexInLayer, e);
+			if (!isVisited(w)) {
+			    traverseDiscovery(e, vertexInLayer);
+
+			    if (isDone())
+				break;
+
+			    visit(w);
+			    layers.get(i + 1).addLast(w);
+
+			    if (isDone())
+				break;
+			} else {
+			    traverseCross(e, v);
+			    if (isDone())
+				break;
+			}
+		    }
+		}
+
+		if (!isDone())
+		    finishVisit(vertexInLayer);
+	    }
+
+	    i++;
+	}
+
+	return result();
+    }
+
+    protected void initResult() {
+    }
+
+    protected void startVisit(Vertex<V> v) {
+    }
+
+    protected void traverseCross(Edge<E> e, Vertex<V> v) {
+    }
+
+    protected void traverseDiscovery(Edge<E> e, Vertex<V> v) {
+    }
+
+    protected void finishVisit(Vertex<V> v) {
+    }
+
+    protected boolean isDone() {
+	return false;
+    }
+
+    protected R result() {
+	return null;
+    }
+
+    protected R finalResult(R r) {
+	return null;
+    }
+
+    protected void visit(DecorablePosition<?> p) throws InvalidKeyException{
+	p.put(STATUS, VISITED);
+    }
+
+    protected void unVisit(DecorablePosition<?> p) throws InvalidKeyException {
+	p.put(STATUS, UNVISITED);
+    }
+
+    protected boolean isVisited(DecorablePosition<?> p) throws InvalidKeyException {
+	return p.get(STATUS) == VISITED;
+    }
+}