code: public void mapFunction(String prefix, String function, Method meth) {
          getELContext().getFunctionMapper().mapFunction(prefix, function, meth);
      }
docs: Maps a static method to an EL function.
  @param prefix The namespace of the functions, can be "".
  @param function The name of the function.
  @param meth The static method to be invoked when the function is used.