public static boolean isTableFunction(String functionName)
      throws SemanticException {
    FunctionInfo tFInfo = getFunctionInfo(functionName);
    return tFInfo != null && !tFInfo.isInternalTableFunction() && tFInfo.isTableFunction();
  }
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