public void visit(OActivity oactivity) {
    String actId = oactivity.getXPath();
    if (actId != null) {
      System.out.println(
          "Adding static ACTIVITY fact: "
              + oactivity.toString()
              + " ("
              + oactivity.getXPath()
              + ")");

      String parentId = "-1";
      if (oactivity.getParent() != null) {
        parentId = oactivity.getParent().getXPath();
      }

      activities.add(new ODEStaticActivityFact(actId, parentId));

    } else {
      System.out.println("Found OActivity without xpath: " + oactivity.getClass().getSimpleName());
    }
  }