code: public String getSplitNodes() {
      if (!isMapTask() || jobSetup || jobCleanup) {
        return "";
      }
      String[] nodes = rawSplit.getLocations();
      if (nodes == null || nodes.length == 0) {
        return "";
      }
      StringBuffer ret = new StringBuffer(nodes[0]);
      for(int i = 1; i < nodes.length;i++) {
        ret.append(",");
        ret.append(nodes[i]);
      }
      return ret.toString();
    }
docs: Gets the Node list of input split locations sorted in rack order.