Cd_graph {

{{

 HashSet definedClasses = new HashSet();
 public void checkForUndefinedClasses(ClassGraph cg) {

    Strategy sg = new Strategy("from Cd_graph bypassing Construct_ns to Vertex");
    TraversalGraph tg = new TraversalGraph(sg,cg);
    
    definedClasses = (HashSet) 
    tg.traverse( this, new Visitor() {
      HashSet hash;
      public void start(){hash = new HashSet();}
      public void before(Vertex host){ 
	Ident vertex_nm = host.get_vertex_name();
	hash.add(vertex_nm);
      }
      public Object getReturnValue(){return hash;}	
    });
    Strategy sg2 = new Strategy("from Cd_graph through Construct_ns to Vertex");
    TraversalGraph tg2 = new TraversalGraph(sg2,cg);
    
    tg2.traverse( this, new Visitor() {
      public void before(Vertex host){ 
	Ident vname = host.get_vertex_name();
	if(!definedClasses.contains(vname)) {
	  System.out.println(" *** ERROR DETECTED: Class " + vertex_nm + " is not defined in the cd file. *** "); 
	}
      }	
    });
 }
}}
}