public void removeOperationGraphListener(OperationGraphListener lst) {
graphListeners.remove(lst);
}
private void installToolbar() {
OperationGraphToolbar toolbar = new OperationGraphToolbar();
toolbar.addContribution(new OnSuccessToolbarContribution(controller));
toolbar.addContribution(new OnFailureToolbarContribution(controller));
toolbar.register(graph);
graph.getOverlayContainer().addOverlay(toolbar.getUi(), OverlayCornerPositioner.UPPER_RIGHT);
}