} else if (obj instanceof Task) { taskAdded((Task) obj);
  public void execute(EnvelopeTuple o, Collection changes) {    // drop changes    Object obj = o.getObject();    if (o.isRemove()) {      if (obj instanceof Task) {  // task        taskRemoved((Task) obj);      }else  if (obj instanceof PlanElement) {                    // PE        planElementRemoved((PlanElement) obj);      }    } else if (o.isAdd()) {      if (obj instanceof DeferredRescind) {        processDeferredRescind((DeferredRescind) obj);      } else if (obj instanceof PlanElement) {        planElementAdded((PlanElement) obj);      }    }  }