狀態(tài)模式
“小菜，你們的加班沒完沒了了？”大鳥為晚上十點(diǎn)才到家的小菜打開了房門。
“嗨，沒辦法，公司的項(xiàng)目很急，所以要求要加班。”
“有這么急嗎？這星期四天來你都在加班，有加班費(fèi)嗎？難道周末也要繼續(xù)？”
“哪來什么加班費(fèi)，周末估計(jì)是逃不了了。”小菜顯然很疲憊，“經(jīng)歷把每個(gè)人每天的工作都排得滿滿的，說做完就可以回家，但是沒有任何一個(gè)人可以在下班前完成的，基本都得加班，這就等于是資源加班。我走時(shí)還有哥們在加班呢。”
“再急也不能這樣呀，長時(shí)間甲苯又沒有加班費(fèi)，士氣更低落，效率大打折扣。”
“可不是！上午剛上班的時(shí)候，效率很高，可以寫不少代碼，到了中午，午飯一吃完，就犯困，可能是最近太累了，但還不敢休息，因?yàn)闆]人趴著睡覺的，都說項(xiàng)目急，要抓緊。所以我就這么迷迷糊糊的，到了下午三點(diǎn)多才略微精神點(diǎn)，本想著今天任務(wù)還算可以，希望能早點(diǎn)完成，爭取不要再加班了。哪知快下班時(shí)才發(fā)現(xiàn)有一個(gè)功能是我理解有誤，其實(shí)比想想的要復(fù)雜得多。嗨！苦呀，又多花了三個(gè)多鐘頭，九點(diǎn)多才從公司出來。”
“那你用代碼來實(shí)現(xiàn)一下你說的這些狀態(tài)吧。”
工作狀態(tài)-函數(shù)版
#include <stdio.h>
static int Hour = 0; // 鐘點(diǎn)
static bool WorkFinished = false; // 任務(wù)完成標(biāo)記
static void WriteProgram()
{
if(Hour < 12)
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 上午工作，精神百倍\n",Hour);
}
else if(Hour < 13)
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 餓了，午飯；犯困，午休。\n",Hour);
}
else if(Hour < 17)
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 下午狀態(tài)還不錯，繼續(xù)努力\n",Hour);
}
else
{
if(WorkFinished)
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 下班回家了\n",Hour);
}
else
{
if(Hour < 21)
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 加班哦，疲累之極\n",Hour);
}
else
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 不行了，睡著了。\n",Hour);
}
}
}
}
int main()
{
Hour = 9;
WriteProgram();
Hour = 10;
WriteProgram();
Hour = 12;
WriteProgram();
Hour = 13;
WriteProgram();
Hour = 14;
WriteProgram();
Hour = 17;
WriteProgram();
WorkFinished = true;
WriteProgram();
Hour = 19;
WriteProgram();
Hour = 22;
WriteProgram();
return 0;
}
“小菜，都學(xué)了這么長時(shí)間的面向?qū)ο箝_發(fā)，你怎么還在寫面向過程的代碼呀？”
“啊，我習(xí)慣性思維了，你意思是說要分一個(gè)類出來。”
“這是起碼的面向?qū)ο笏季S呀，至少應(yīng)該有個(gè)“工作”類，你的‘寫程序’方法是類方法，而‘鐘點(diǎn)’、‘任務(wù)完成’其實(shí)就是類的什么？”
“應(yīng)該是對外屬性，是吧？”
“問什么問，還不快去重寫。”
工作狀態(tài)-分類版
#include <stdio.h>
class Work
{
public:
int Hour; // 鐘點(diǎn)
bool WorkFinished; // 任務(wù)完成標(biāo)記
void WriteProgram()
{
if(Hour < 12)
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 上午工作，精神百倍\n",Hour);
}
else if(Hour < 13)
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 餓了，午飯；犯困，午休。\n",Hour);
}
else if(Hour < 17)
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 下午狀態(tài)還不錯，繼續(xù)努力\n",Hour);
}
else
{
if(WorkFinished)
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 下班回家了\n",Hour);
}
else
{
if(Hour < 21)
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 加班哦，疲累之極\n",Hour);
}
else
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 不行了，睡著了。\n",Hour);
}
}
}
}
};
int main()
{
Work* emergencyProjects = new Work();
emergencyProjects->Hour = 9;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 10;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 12;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 13;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 14;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 17;
emergencyProjects->WorkFinished = false;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 19;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 22;
emergencyProjects->WriteProgram();
delete emergencyProjects;
return 0;
}
方法過長是壞味道。
狀態(tài)模式
狀態(tài)模式主要解決的是當(dāng)控制一個(gè)對象狀態(tài)轉(zhuǎn)換的條件表達(dá)式國語復(fù)雜時(shí)的情況。把狀態(tài)的判斷邏輯轉(zhuǎn)移到表示不同狀態(tài)的一系列類當(dāng)中，可以把復(fù)雜的判斷邏輯簡化。
實(shí)現(xiàn)方式(UML類圖)
實(shí)現(xiàn)代碼
#include <stdio.h>
class State;
// 工作
class Work
{
public:
Work();
~Work();
void SetState(State* s);
void WriteProgram();
int Hour;
bool Finished;
protected:
State* current;
};
// 抽象狀態(tài)
class State
{
public:
virtual void WriteProgram(Work* w)=0;
};
// 下班休息狀態(tài)
class RestState : public State
{
public:
virtual void WriteProgram(Work* w)
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 下班回家了\n",w->Hour);
}
};
// 睡眠狀態(tài)
class SleepingState : public State
{
public:
virtual void WriteProgram(Work* w)
{
printf("當(dāng)前時(shí)間：%d點(diǎn) 不行了，睡著了。\n",w->Hour);
}
};
// 晚間工作狀態(tài)
class EveningState : public State
{
public:
virtual void WriteProgram(Work* w)
{
if(w->Finished)
{
w->SetState(new RestState());
w->WriteProgram();
}
else
{
if(w->Hour < 21) printf("當(dāng)前時(shí)間：%d點(diǎn) 加班哦，疲累之極\n",w->Hour);
else
{
w->SetState(new SleepingState());
w->WriteProgram();
}
}
}
};
// 下午工作狀態(tài)
class AfternoonState : public State
{
public:
virtual void WriteProgram(Work* w)
{
if(w->Hour < 17) printf("當(dāng)前時(shí)間：%d點(diǎn) 下午狀態(tài)還不錯，繼續(xù)努力\n",w->Hour);
else
{
w->SetState(new EveningState());
w->WriteProgram();
}
}
};
// 中午工作狀態(tài)
class NoonState : public State
{
public:
virtual void WriteProgram(Work* w)
{
if(w->Hour < 13) printf("當(dāng)前時(shí)間：%d點(diǎn) 餓了，午飯；犯困，午休。\n",w->Hour);
else
{
w->SetState(new AfternoonState());
w->WriteProgram();
}
}
};
// 上午工作狀態(tài)
class ForenoonState : public State
{
public:
virtual void WriteProgram(Work* w)
{
if(w->Hour < 12) printf("當(dāng)前時(shí)間：%d點(diǎn) 上午工作，精神百倍\n",w->Hour);
else
{
w->SetState(new NoonState());
w->WriteProgram();
}
}
};
Work::Work()
{
current = new ForenoonState();
}
Work::~Work()
{
delete current;
}
void Work::SetState(State* s)
{
delete current;
current = s;
}
void Work::WriteProgram()
{
current->WriteProgram(this);
}
int main()
{
Work* emergencyProjects = new Work();
emergencyProjects->Hour = 9;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 10;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 12;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 13;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 14;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 17;
emergencyProjects->Finished = false;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 19;
emergencyProjects->WriteProgram();
emergencyProjects->Hour = 22;
emergencyProjects->WriteProgram();
delete emergencyProjects;
return 0;
}
運(yùn)行結(jié)果
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posted on 2011-07-03 22:05
lwch 閱讀(2816)
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設(shè)計(jì)模式