public static boolean isNoopFunction(String fnName) {
    fnName = fnName.toLowerCase();
    return fnName.equals(NOOP_MAP_TABLE_FUNCTION) ||
        fnName.equals(NOOP_STREAMING_MAP_TABLE_FUNCTION) ||
        fnName.equals(NOOP_TABLE_FUNCTION) ||
        fnName.equals(NOOP_STREAMING_TABLE_FUNCTION);
  }
Both UDF and UDAF functions can imply order for analytical functions

@param functionName
         name of function
@return true if a GenericUDF or GenericUDAF exists for this name and implyOrder is true, false
        otherwise.
@throws SemanticException
ql/src/java/org/apache/hadoop/hive/ql/exec/FunctionRegistry.java