public static String[] getQualifiedFunctionNameParts(String name) throws HiveException {
    if (isQualifiedFunctionName(name)) {
      return splitQualifiedFunctionName(name);
    }
    String dbName = SessionState.get().getCurrentDatabase();
    return new String[] { dbName, name };
  }
Splits a qualified function name into an array containing the database name and function name.
If the name is not qualified, the database name is null.
If there is more than one '.', an exception will be thrown.
@param functionName Function name, which may or may not be qualified
@return
ql/src/java/org/apache/hadoop/hive/ql/exec/FunctionUtils.java