@Override
    public boolean matches(RelOptRuleCall call) {
      final HiveFilter filter = call.rel(0);
      final HiveJdbcConverter conv = call.rel(1);
      return canSplitFilter(filter.getCondition(), conv.getJdbcDialect());
    }
JDBCSplitFilterRule splits a HiveFilter rule so we could push part of the HiveFilter into the jdbc.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/jdbc/JDBCAbstractSplitFilterRule.java