+ if (path == null)\r
+ throw new UnsupportedException("Cannot register under a null path.");\r
+ if (element == null)\r
+ throw new UnsupportedException(\r
+ "Cannot register null element for path " + path);\r
+ if (element.getLabel() == null)\r
+ throw new UnsupportedException(\r
+ "Cannot register an element with null label for path "\r
+ + path);\r
+\r