private void evaluateWork(BaseWork w) throws SemanticException {

      if (w instanceof MapWork) {
        evaluateMapWork((MapWork) w);
      } else if (w instanceof ReduceWork) {
        evaluateReduceWork((ReduceWork) w);
      } else if (w instanceof MergeJoinWork) {
        evaluateMergeWork((MergeJoinWork) w);
      } else {
        LOG.info("We are not going to evaluate this work type: " + w.getClass().getCanonicalName());
      }
    }
SerializeFilter is a simple physical optimizer that serializes all filter expressions in
Tablescan Operators.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/physical/SerializeFilter.java