Composite模式

来源：互联网发布：java 注释 link 编辑：程序博客网时间：2024/06/06 07:14

在开发时，如果遇到使用递归构建树状的组合结构，那么可以考虑使用Composite模式．Composite模式将对象组合成树形结构，来表示部分，整体的层次结构．
解决整合与部分可以被一致对待问题。

其类结构如图所示：
这里写图片描述

在Component中声明可所有管理子类对象的方法，因此实现Component接口的子类都有了Add，Remove等功能，这样叶子节点和枝节点对于外界没有区别；但是因为Leaf类本身不具备Add，Remove等功能，实现也没有意义．

在实现时，管理叶子节点需要容器，这里使用了vector．

//Component.h

//Component.h#ifndef _COMPONENT_H_#define _COMPONENT_H_class Component{public:    Component();    virtual ~Component();    virtual void Operation() = 0;    virtual void Add(const Component&);    virtual void Remove(const Component&);    virtual Component* GetChild(int);};#endif

//Component.cpp

//Component.cpp#include"Component.h"Component::Component(){}Component::~Component(){}void Component::Add(const Component& com){}void Component::Remove(const Component& com){}Component* Component::GetChild(int index){    return 0;}

//Composite.h

//Composite.h#ifndef _COMPOSITE_H_#define _COMPOSITE_H_#include"Component.h"#include<vector>class Composite :public Component{public:    Composite();    ~Composite();    void Operation();    void Add(Component* com);    void Remove(Component* com);    Component* GetChild(int index);private:    std::vector<Component*> comVec;};#endif

//Composite.cpp

//Composite.cpp#include"Component.h"#include"Composite.h"Composite::Composite(){}Composite::~Composite(){}void Composite::Operation(){    std::vector<Component*>::iterator comIter = comVec.begin();    for (; comIter != comVec.end(); comIter++)    {        (*comIter)->Operation();    }}void Composite::Add(Component* com){    comVec.push_back(com);}void Composite::Remove(Component* com){    std::vector<Component*>::iterator comIter = comVec.begin();    for (; comIter != comVec.end(); comIter++)    {        if (*comIter == com)        {            comVec.erase(comIter);            return;        }    }}Component* Composite::GetChild(int index){    return comVec[index];}

//Leaf.h

//Leaf.h#ifndef _LEAF_H_#define _LEAF_H_#include"Component.h"class Leaf :public Component{public:    Leaf();    ~Leaf();    void Operation();};#endif

//Leaf.cpp

//Leaf.cpp#include"Leaf.h"#include<iostream>Leaf::Leaf(){}Leaf::~Leaf(){}void Leaf::Operation(){    std::cout << "Leaf operation..." << std::endl;}

//main.cpp

//main.cpp#include"Component.h"#include"Composite.h"#include"Leaf.h"int main(){    Leaf* l = new Leaf();    l->Operation();    Composite *com = new Composite();    com->Add(l);    com->Operation();    Component* ll = com->GetChild(0);    ll->Operation();    return 0;}

0 0