@Override
  public String getDisplayString(String[] children) {
    return String.format("%s(%s)", processor.getClass().getSimpleName(), children[1]);
  }
GenericUDF Class for support of "INTERVAL (expression) (DAY|YEAR|...)".
ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFInternalInterval.java