public TrafficLightYellowState(TrafficLight trafficLight, Light yellowLight)
{
_trafficLight = trafficLight;
_yellowLight = yellowLight;
_trafficLight.OnLightStateChanged += (previousLight) => _previousLight = previousLight;
}
void Start()
{
YellowState = new TrafficLightYellowState(this, _yellowLight);
RedState = new TrafficLightRedState(this, _redLight);
GreenState = new TrafficLightGreenState(this, _greenLight);
_currentState = GreenState;
_currentState.Enter();
}
public void ChangeState(ITrafficLightState state)
{
if (OnLightStateChanged != null)
{
OnLightStateChanged.Invoke(_currentState);
}
_currentState.Exit();
_currentState = state;
state.Enter();
}
/// <summary>
/// 設置燈號
/// </summary>
/// <param name="state">燈號狀態</param>
/// <returns>燈號</returns>
public LightStateEnum SetState(ITrafficLightState state)
{
if (!state.CheckContext(this.State))
{
return(LightStateEnum.Null);
}
else
{
this.State = state;
return(this.State.GetLightState());
}
}
protected void Toggle()
{
Lights = Lights switch
{
StopState _ => new GetReadyToGoState(),
GetReadyToGoState _ => new GoState(),
GoState _ => new GetReadyToStopState(),
GetReadyToStopState _ => new StopState(),
_ => throw new ArgumentOutOfRangeException(nameof(Lights))
};
}
}
/// <summary>
/// Ctor for <see cref="YellowState"/> that takes previous <see cref="TrafficLight"/> state
/// </summary>
/// <param name="state">previous <see cref="TrafficLight"/> state</param>
/// <exception cref="ArgumentNullException">Throws when <paramref name="state"/> is equal to null</exception>
public YellowState(ITrafficLightState state)
{
_previousState = state ?? throw new ArgumentNullException($"{nameof(state)} can't be equal to null!");
}
/// <summary>
/// 檢查當前狀態是否能進入目標狀態
/// </summary>
/// <param name="state">當前狀態</param>
/// <returns>檢查結果boolean</returns>
public bool CheckContext(ITrafficLightState state)
{
return(state.GetLightState() == LightStateEnum.Red);
}
/// <summary>
/// Standart ctor for <see cref="TrafficLight"/>
/// </summary>
public TrafficLight()
{
State = new GreenState();
}
/// <summary>
/// 切換燈號
/// </summary>
/// <returns>回傳切換後的燈號</returns>
public LightStateEnum Request()
{
this.State = this.State.Handle();
return(this.State.GetLightState());
}
/// <summary>
/// 建構子
/// </summary>
/// <param name="state">燈號狀態</param>
public TrafficLightContext(ITrafficLightState state)
{
this.State = state;
}
public void Update()
{
_state = _state.Change();
}
public TrafficLight()
{
_state = new RedLight();
}
public TrafficLightV2(ITrafficLightState trafficLightState)
{
State = trafficLightState;
}
internal async Task MoveNext(ITrafficLightState state = null)
{
this.State = state ?? new GreenState();
await this.State.Handle(this);
}
public TrafficLight(ITrafficLightState ws)
{
State = ws;
}
