40 lines
1.0 KiB
C++
40 lines
1.0 KiB
C++
/**
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* @name 状态模式
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* @brief: 允许对象在内部状态改变时改变行为
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* @note 场景：订单状态机、游戏角色状态、电梯控制
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*/
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class OrderState {
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public:
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virtual void shipOrder(Order* order) = 0;
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virtual void cancelOrder(Order* order) = 0;
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};
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class NewState : public OrderState {
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void shipOrder(Order* order) override {};
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void cancelOrder(Order* order) override {};
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};
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class ShippedState : public OrderState {
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void shipOrder(Order* order) override { /* 已发货，不可重复操作 */ }
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void cancelOrder(Order* order) override { /* 已发货不可取消 */ }
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};
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class Order {
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public:
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Order() : state(new NewState()) {}
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void ship() { state->shipOrder(this); }
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void cancel() { state->cancelOrder(this); }
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void changeState(OrderState* newState) {
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delete state;
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state = newState;
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}
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private:
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OrderState* state;
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};
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// 状态转换实现
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void NewState::shipOrder(Order* order) {
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// 发货逻辑...
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order->changeState(new ShippedState());
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} |