void markFailed() {
    // It's possible that the dag is killed before this method is called.
    assertRunningOrKilling();
    changeStatus(Status.FAILURE);
    for (final Node child : this.children) {
      child.cancel();
    }
    //todo: HappyRay support failure options "Finish Current Running" and "Cancel All"
    this.dag.updateDagStatus();
  }
void markFailed ( ) { assertRunningOrKilling ( ) ; changeStatus ( Status . FAILURE ) ; for ( final Node child : this . children ) { child . cancel ( ) ; } this . dag . updateDagStatus ( ) ; }
Transitions the node to the failure state.