设计模式复习-访问者模式
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设计模式复习-访问者模式
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VisitorMode.h#pragma once
#include<list>
#include<string>
#include<iostream>
using namespace std;/*
设计模式-访问者模式（Visitor）
表示一个作用于某对象机构中各元素的操作。它使你可以在不改变各元素的类的前提下定义作用于
这些元素的新操作。
*/class CConcreteElementA;
class CConcreteElementB;class CVisitor {//为该对象结构中ConcreteElement的每个类声明一个Visit操作。
public:virtual void VisitConcreteElementA(CConcreteElementA * pConcreteElementA) = 0;virtual void VisitConcreteElementB(CConcreteElementB * pConcreteElementB) = 0;
};class ConcreteVisitor1 :public CVisitor {//具体访问者类
public:void VisitConcreteElementA(CConcreteElementA * pConcreteElementA);void VisitConcreteElementB(CConcreteElementB * pConcreteElementB);
};class ConcreteVisitor2 :public CVisitor {//具体访问者类
public:void VisitConcreteElementA(CConcreteElementA * pConcreteElementA);void VisitConcreteElementB(CConcreteElementB * pConcreteElementB);
};class CElement {//定义一个Accept操作,它以一个访问者为参数
public:virtual void Accept(CVisitor *pVisitor) = 0;
};class CConcreteElementA :public CElement {
private:string mstrName;
public:CConcreteElementA(const string &strName);void Accept(CVisitor *pVisitor);void OperationA() {}//A的单独方法string GetName();
};class CConcreteElementB :public CElement {
private:string mstrName;
public:CConcreteElementB(const string &strName);void Accept(CVisitor *pVisitor);void OperationB() {}//B的单独方法string GetName();
};class CobjuctStructure {//定义一个高层接口，以允许访问者访问它的元素。
private:list<CElement*>mlElement;
public:CobjuctStructure();~CobjuctStructure();void Attach(CElement *pElement);void Eetach(CElement *pElement);void Accept(CVisitor *pVisitor);
};VisitorMode.cpp
#include "stdafx.h"
#include "VisitorMode.h"void ConcreteVisitor1::VisitConcreteElementA(CConcreteElementA * pConcreteElementA) {cout << "1-A:" << pConcreteElementA->GetName() << endl;
}
void ConcreteVisitor1::VisitConcreteElementB(CConcreteElementB * pConcreteElementB) {cout << "1-B:" << pConcreteElementB->GetName() << endl;
}void ConcreteVisitor2::VisitConcreteElementA(CConcreteElementA * pConcreteElementA) {cout << "2-A:" << pConcreteElementA->GetName() << endl;
}
void ConcreteVisitor2::VisitConcreteElementB(CConcreteElementB * pConcreteElementB) {cout << "2-B:" << pConcreteElementB->GetName() << endl;
}CConcreteElementA::CConcreteElementA(const string &strName) {mstrName = strName;}
void CConcreteElementA::Accept(CVisitor *pVisitor) {pVisitor->VisitConcreteElementA(this);
}
string CConcreteElementA::GetName() {return mstrName;
}CConcreteElementB::CConcreteElementB(const string &strName) {mstrName = strName;}
void CConcreteElementB::Accept(CVisitor *pVisitor) {pVisitor->VisitConcreteElementB(this);
}
string CConcreteElementB::GetName() {return mstrName;
}CobjuctStructure::CobjuctStructure() {mlElement.clear();
}
CobjuctStructure::~CobjuctStructure() {for each(CElement* index in mlElement) {delete index;}
}
void CobjuctStructure::Attach(CElement *pElement) {mlElement.push_back(pElement);
}
void CobjuctStructure::Eetach(CElement *pElement) {mlElement.remove(pElement);
}
void CobjuctStructure::Accept(CVisitor *pVisitor) {for each (CElement * index in mlElement) {index->Accept(pVisitor);}
}客户端调用#include<string>
#include<iostream>
#include "VisitorMode.h"
using namespace std;int main() {CobjuctStructure *pO = new CobjuctStructure();pO->Attach(new CConcreteElementA("man"));pO->Attach(new CConcreteElementB("woman"));ConcreteVisitor1 *pV1 = new ConcreteVisitor1();ConcreteVisitor2 *pV2 = new ConcreteVisitor2();pO->Accept(pV1);pO->Accept(pV2);delete pO, delete pV1, delete pV2;getchar();return 0;
}
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