@SuppressWarnings("unchecked")
  protected boolean allParentsDispatched(Node nd) {
    Operator<? extends OperatorDesc> op = (Operator<? extends OperatorDesc>) nd;
    if (op.getParentOperators() == null) {
      return true;
    }
    for (Node pNode : op.getParentOperators()) {
      if (!getDispatchedList().contains(pNode)) {
        return false;
      }
    }
    return true;
  }
Constructor.

@param disp
dispatcher to call for each op encountered
ql/src/java/org/apache/hadoop/hive/ql/lib/ForwardWalker.java