@Override
    public FilterPredicate buildPredict(Operator op, Object literal,
                                        String columnName, TypeInfo columnType) {
      switch (op) {
        case LESS_THAN:
          return lt(intColumn(columnName), ((Number) literal).intValue());
        case IS_NULL:
        case EQUALS:
        case NULL_SAFE_EQUALS:
          return eq(intColumn(columnName),
            (literal == null) ? null : ((Number) literal).intValue());
        case LESS_THAN_EQUALS:
          return ltEq(intColumn(columnName), ((Number) literal).intValue());
        default:
          throw new RuntimeException("Unknown PredicateLeaf Operator type: " + op);
      }
    }
@param op         consists of EQUALS, NULL_SAFE_EQUALS, LESS_THAN, LESS_THAN_EQUALS, IS_NULL
@param literal
@param columnName
@param columnType
@return
ql/src/java/org/apache/hadoop/hive/ql/io/parquet/LeafFilterFactory.java