2、智能空调的设计与实现
某软件公司将开发一套智能空调系统： 系统检测到温度处于20---30度之间，则切换到常温状态；温度处于30---45度，则切换到制冷状态； 温度小于20度，则切换到制热状态。请使用状态模式对此系统进行设计。
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从需求中可以看出，空调可以处于三种状态: 制热状态、常温状态、制冷状态。每种状态下都存在三种行为:保持常温、制冷、制热。
空调抽象状态实现代码如下:
//空调抽象状态类
class AirConditionerState
{
public:
//保持常温
virtual void KeepNormalTemperature(AirConditioner * pAirConditioner) = 0;
//制冷
virtual void refrigerate(AirConditioner * pAirConditioner) = 0;
//制热
virtual void Heat(AirConditioner * pAirConditioner) = 0;
}; 三种具体状态类声明如下:
//常温状态
class NormalTemperatureState : public AirConditionerState
{
public:
//保持常温
void KeepNormalTemperature(AirConditioner * pAirConditioner);
//制冷
void refrigerate(AirConditioner * pAirConditioner);
//制热
void Heat(AirConditioner * pAirConditioner);
};
//制冷状态
class RefrigerateState : public AirConditionerState
{
public:
//保持常温
void KeepNormalTemperature(AirConditioner * pAirConditioner);
//制冷
void refrigerate(AirConditioner * pAirConditioner);
//制热
void Heat(AirConditioner * pAirConditioner);
};
//制热状态
class HeatState : public AirConditionerState
{
public:
//保持常温
void KeepNormalTemperature(AirConditioner * pAirConditioner);
//制冷
void refrigerate(AirConditioner * pAirConditioner);
//制热
void Heat(AirConditioner * pAirConditioner);
}; 每种状态下都存在保持常温、制冷、制热方法。这些方法带有一个AirConditioner类参数，方法内部使用这个参数回调空调的温度值，根据这个温度值，用于判断该方法如何实现，以及如何切换到其他状态。三种状态实现代码如下:
/******************************正常温度状态******************************************/
//保持常温
void NormalTemperatureState::KeepNormalTemperature(AirConditioner * pAirConditioner)
{
int nTemperature = pAirConditioner->GetTemperature();
if( nTemperature > 20 && nTemperature <= 30 )
{
cout << "已经是常温状态，不能调节为常温" << endl;
}
}
//制冷
void NormalTemperatureState::refrigerate(AirConditioner * pAirConditioner)
{
int nTemperature = pAirConditioner->GetTemperature();
if( nTemperature > 30 && nTemperature <= 45 )
{
pAirConditioner->SetAirConditionerState(pAirConditioner->GetRefrigerateState());
cout << "切换到制冷状态" << endl;
}
}
//制热
void NormalTemperatureState::Heat(AirConditioner * pAirConditioner)
{
int nTemperature = pAirConditioner->GetTemperature();
if( nTemperature <= 20 )
{
pAirConditioner->SetAirConditionerState(pAirConditioner->GetHeatState());
cout << "切换到制热状态" << endl;
}
}
/******************************制冷状态******************************************/
//保持常温
void RefrigerateState::KeepNormalTemperature(AirConditioner * pAirConditioner)
{
int nTemperature = pAirConditioner->GetTemperature();
if( nTemperature > 20 && nTemperature <= 30 )
{
pAirConditioner->SetAirConditionerState(pAirConditioner->GetNormalTemperatureState());
cout << "切换到常温状态" << endl;
}
}
//制冷
void RefrigerateState::refrigerate(AirConditioner * pAirConditioner)
{
int nTemperature = pAirConditioner->GetTemperature();
if( nTemperature > 30 && nTemperature <= 45 )
{
cout << "已经是制冷状态，不能调节为制冷状态" << endl;
}
}
//制热
void RefrigerateState::Heat(AirConditioner * pAirConditioner)
{
int nTemperature = pAirConditioner->GetTemperature();
if( nTemperature <= 20 )
{
pAirConditioner->SetAirConditionerState(pAirConditioner->GetHeatState());
cout << "切换到制热状态" << endl;
}
}
/******************************制热状态******************************************/
//保持常温
void HeatState::KeepNormalTemperature(AirConditioner * pAirConditioner)
{
int nTemperature = pAirConditioner->GetTemperature();
if( nTemperature > 20 && nTemperature <= 30 )
{
pAirConditioner->SetAirConditionerState(pAirConditioner->GetNormalTemperatureState());
cout << "切换到常温状态" << endl;
}
}
//制冷
void HeatState::refrigerate(AirConditioner * pAirConditioner)
{
int nTemperature = pAirConditioner->GetTemperature();
if( nTemperature > 30 && nTemperature <= 45 )
{
pAirConditioner->SetAirConditionerState(pAirConditioner->GetRefrigerateState());
cout << "切换到制冷状态" << endl;
}
}
//制热
void HeatState::Heat(AirConditioner * pAirConditioner)
{
int nTemperature = pAirConditioner->GetTemperature();
if( nTemperature <= 20 )
{
cout << "已经是制热状态，不能调节为制热状态" << endl;
}
} 空调类，也就是环境类Contex,维护了一个状态的引用，实现的时候将调用状态对象的方法。声明代码如下:
//空调类
class AirConditioner
{
private:
//空调名称
string m_strAirName;
//空调当前温度
int m_nTemperature;
//常温状态
AirConditionerState * m_pNormalTemperatureState;
//制冷状态
AirConditionerState * m_pRefrigerateState;
//制热状态
AirConditionerState * m_pHeatState;
//当前温度状态
AirConditionerState * m_pCurState;
public:
//构造函数
AirConditioner(string strAirName, int nTemperature);
//虚构函数
~AirConditioner();
//调节温度
void SetTemperature(int nTemperature);
//获取温度
int GetTemperature();
//设置空调状态
void SetAirConditionerState(AirConditionerState * pAirConditionerState);
//获取常温状态
AirCondi