@Override
    public int compareTo(Dependency o) {
      int compare = getName().compareTo(o.getName());
      if (compare == 0) {
        compare = getType().compareTo(o.getType());
      }
      return compare;
    }
returns the edge type connecting work a and b
ql/src/java/org/apache/hadoop/hive/ql/plan/TezWork.java