public void warn(Event event) {
		switch(event.getTypeEvent())
		{
		case ROBOT_DETECTED :
			if(state == 1)
				state = -1;
			else
				ignore();
			break;
		case ROTATE_END :
			if(state == 0)
				state = 1;
			else if(state == 2)
				state = 3;
			else
				ignore();
			break;
		case GOFORWARD_END :
			if(state == 1)
				state = 2;
			else
				ignore();
			break;
		case CHILDBEHAVIOR_END :
			if(state == -1)
				state = 0;
			else
				ignore();
			break;
		default:
			ignore();
			break;
		}
	}