@Explain(displayName = "Edges", explainLevels = { Level.USER, Level.DEFAULT, Level.EXTENDED },
      vectorization = Vectorization.SUMMARY_PATH)
  public Map<String, List<Dependency>> getDependencyMap() {
    Map<String, List<Dependency>> result = new LinkedHashMap<String, List<Dependency>>();
    for (Map.Entry<BaseWork, List<BaseWork>> entry: invertedWorkGraph.entrySet()) {
      List dependencies = new LinkedList<Dependency>();
      for (BaseWork d: entry.getValue()) {
        Dependency dependency = new Dependency();
        dependency.w = d;
        dependency.type = getEdgeType(d, entry.getKey());
        dependencies.add(dependency);
      }
      if (!dependencies.isEmpty()) {
        Collections.sort(dependencies);
        result.put(entry.getKey().getName(), dependencies);
      }
    }
    return result;
  }
returns the edge type connecting work a and b
ql/src/java/org/apache/hadoop/hive/ql/plan/TezWork.java