设计模式09——组合模式

 

用例：

//composite.cpp
//组合模式：将对象组合成树形结构以表“部分-整体”的层次结构。

#include "gtest/gtest.h"
#include <string>
#include <list>

class Component
{
public:
    Component() {}
    virtual ~Component() {}

    virtual int Add(Component*) = 0;
    virtual int Remove(Component*) = 0;
    virtual int Operation() = 0;
};

class Leaf : public Component
{
public:
    Leaf(std::string n) : name(n) {}
    ~Leaf() {}

    int Add(Component* c)
    {
        return 0;
    }

    int Remove(Component* c)
    {
        return 0;
    }

    int Operation()
    {
        return int('L');
    }

private:
    std::string name;
};


class Composite : public Component
{
public:
    Composite(std::string n) : name(n) {}
    ~Composite() 
    {
        std::list<Component*>::iterator i;
        for (i = lst.begin();i != lst.end();i++)
        {
            delete *i;
        }
    }

    int Add(Component* c)
    {
        lst.push_back(c);
        return 0;
    }

    int Remove(Component* c)
    {
        lst.remove(c);
        return 0;
    }

    int Operation()
    {
        return int('C');
    }

private:
    std::string name;
    std::list<Component*> lst;
};



TEST(Composite,composite)
{
    Composite* root = new Composite("root");
    root->Add(new Leaf("Leaf A"));
    root->Add(new Leaf("Leaf B"));

    Composite* compo = new Composite("composite1");
    root->Add(new Leaf("Leaf C"));
    root->Add(new Leaf("Leaf D"));

    root->Add(compo);

    delete root;
}