[ff-cvs] fenfire/org/fenfire/util/lava Traversals.java

[Tuukka Hastrup]

CVSROOT:        /cvsroot/fenfire
Module name:    fenfire
Branch:         
Changes by:     Tuukka Hastrup <address@hidden> 03/08/15 19:04:03

Modified files:
        org/fenfire/util/lava: Traversals.java 

Log message:
        added concat Iterator for non-directed properties

CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/fenfire/fenfire/org/fenfire/util/lava/Traversals.java.diff?tr1=1.1&tr2=1.2&r1=text&r2=text

Patches:
Index: fenfire/org/fenfire/util/lava/Traversals.java
diff -u fenfire/org/fenfire/util/lava/Traversals.java:1.1 
fenfire/org/fenfire/util/lava/Traversals.java:1.2
--- fenfire/org/fenfire/util/lava/Traversals.java:1.1   Fri Aug 15 17:49:50 2003
+++ fenfire/org/fenfire/util/lava/Traversals.java       Fri Aug 15 19:04:03 2003
@@ -14,6 +14,38 @@
     static class CollisionException extends Exception {
     }
 
+    /** Returns an iterator of nodes directly connected to a given node
+     *  along a given non-directional property.
+     */
+    static Iterator findConnected_Iter(ConstGraph g, Object node, 
+                                      Object property) {
+       return concat(g.findN_X11_Iter(property, node),  // subjects
+                     g.findN_11X_Iter(node, property)); // objects
+    }
+
+    /** Returns an iterator that iterates given iterators one after the other.
+     */
+    static Iterator concat(final Iterator first, final Iterator second) {
+       return new Iterator() {
+               Iterator active = first;
+               public boolean hasNext() {
+                   if(active.hasNext())
+                       return true;
+                   if(active != second)
+                       return second.hasNext();
+                   return false;
+               }
+               public Object next() {
+                   if(!active.hasNext() && active != second)
+                       active = second;
+                   return active.next();
+               }
+               public void remove() {
+                   active.remove();
+               }
+           };
+    }
+
     /** Tests whether a given nondirected property connects the two
        nodes given. The method is to run BFS from both nodes simultaneously
        and see whether they collide. */
@@ -53,13 +85,13 @@
        while(active.hasNext()) {
            Object node = active.next();
            
-           iterateConns(g.findN_11X_Iter(node, property), visited, activated, 
obstacles);
-           iterateConns(g.findN_X11_Iter(property, node), visited, activated, 
obstacles);
+           iterateConns(findConnected_Iter(g, node, property), visited, 
activated, obstacles);
        }
        return activated;
     }
 
-    /** Iterates connections from some node to visit new nodes. */
+    /** Iterates connections from some node to visit new nodes. 
+        XXX Is this really reusable as it is ?-) */
     static void iterateConns(Iterator conns, Set visited, Set activated, 
                      Set obstacles) throws CollisionException {
        while(conns.hasNext()) {
@@ -72,4 +104,5 @@
            }
        }
     }
+
 }