public static Classifier getClassifier(Set objects, Class rootType, long rootID, int m, Registry ctx)
public static Classifier getClassifier(JFrame parent, Set objects, Class rootType, long rootID, int m, Registry ctx)
    public static Classifier getClassifier(Set objects, Class rootType,     									long rootID, int m, Registry ctx)    {    	if (registry == null) registry = ctx;    	if (objects == null || objects.size() == 0) return null;    	 return singleton.createClassifier(objects, rootType, rootID, m);    }