exended nav

src/main/jastadd/base/Navigation.jrag

@@ -218,13 +218,20 @@ aspect Navigation {
    }
 
    syn Transition PetriNet.getTransitionById(String id) {
-
         for (Transition t : this.allTransitions()) {
             if (t.getId().equals(id)) {
                 return t;
             }
         }
+        return null;
+   }
 
+   syn Place PetriNet.getPlaceById(String id) {
+          for (Place p : this.allPlaces()) {
+              if (p.getId().equals(id)) {
+                return p;
+              }
+          }
           return null;
    }