设计模式——组合模式（C++）

/*****************************************Copyright (c) 2016 Jingshuang Hu@filename:Component.h@datetime:2016.09.19@author:HJS@e-mail:[e-mail]@blog:http://blog.csdn.net/hujingshuang*****************************************/#ifndef _COMPONENT_H#define _COMPONENT_H#include <list>#include <string>// 定义接口class Component {public:    virtual void operation() = 0;    virtual void add(Component* component) = 0;    virtual void remove(Component* component) = 0;    virtual Component* getChild(int index) = 0;};// 叶节点，继承并实现了operation方法// 也继承了add、remove、getChild等操作，但叶节点没有孩子，因此这些方法对叶节点无意义。class Leaf : public Component {private:    std::string name;public:    Leaf(std::string name);    virtual void operation();    virtual void add(Component* component);    virtual void remove(Component* component);    virtual Component* getChild(int index);};// 定义组件，继承并实现了基类中的所有方法，组件可以添加叶节点或新的组件class Composite : public Component {private:    std::string name;    std::list<Component*> *lst;public:    Composite(std::string name);    virtual void operation();    virtual void add(Component* component);    virtual void remove(Component* component);    virtual Component* getChild(int index);};#endif // _COMPONETN_H

/*****************************************Copyright (c) 2016 Jingshuang Hu@filename:Component.cpp@datetime:2016.09.19@author:HJS@e-mail:[e-mail]@blog:http://blog.csdn.net/hujingshuang*****************************************/#include "Component.h"#include <iostream>#include <list>#include <string>using namespace std;// 抽象接口void Component::operation() {}void Component::add(Component* component) {}void Component::remove(Component* component) {}Component* Component::getChild(int index) {     return NULL;}// 叶节点Leaf::Leaf(string name) {    this->name = name;}void Leaf::operation() {    cout << "Leaf:" + name + ":operation" << endl;}void Leaf::add(Component* component) {}void Leaf::remove(Component* component) {}Component* Leaf::getChild(int index) {    return NULL;}// 组件Composite::Composite(string name) {    this->name = name;    lst = new list<Component*>;}void Composite::operation() {    cout << "Composite:" + name + ":operation" << endl;    list<Component*>::iterator it = lst->begin();    for (; it != lst->end(); it++) {        (*it)->operation();    }}void Composite::add(Component* component) {         // 添加叶节点或组件    lst->push_back(component);}void Composite::remove(Component* component) {      // 移除叶节点或组件    lst->remove(component);}Component* Composite::getChild(int index) {    if (index < 0 || index >= lst->size()) {        return NULL;    }    list<Component*>::iterator it = lst->begin();    for (int i = 0; i < index; i++){        it++;    }    return *it;}

/*****************************************Copyright (c) 2016 Jingshuang Hu@filename:main.cpp@datetime:2016.09.19@author:HJS@e-mail:[e-mail]@blog:http://blog.csdn.net/hujingshuang*****************************************/#include <iostream>#include "Component.h"using namespace std;// 简易层次结构// root +---->leafA //      +----->comA  +----->leafB1//                   +----->leafB2//                   +----->comB   +----->leafC//                                 +----->comC  +----->leafD// 以UI设计的角度来看，非常形象，很好理解。int main() {    Component* root = new Composite("root");        // 可看做Panel    Leaf* leafA = new Leaf("A");                    // 可看做控件    Leaf* leafB1 = new Leaf("B1");    Leaf* leafB2 = new Leaf("B2");    Leaf* leafC = new Leaf("C");    Leaf* leafD = new Leaf("D");    Composite* comA = new Composite("A");           // 可看做subPanel    Composite* comB = new Composite("B");    Composite* comC = new Composite("C");    root->add(leafA);    root->add(comA);    comA->add(leafB1);    comA->add(leafB2);    comA->add(comB);    comB->add(leafC);    comB->add(comC);    comC->add(leafD);    root->operation();    comA->remove(comB);    root->operation();    Component* com = comA->getChild(1);    if (com) {        com->operation();    }    system("pause");    return 0;}// 组合模式：允许将对象组合成树形结构来表现“整体-部分”层次结构。组合能让客户以一致的方式处理个别对象以及组合。