组合模式是一种树形递归结构
在需要用到递归构建树形的组合结构,
1.比如文件夹,文件夹里面可以有文件夹,文件,文件夹还可以有文件 文件夹
2.比如多级菜单
3.比如解析XML文件的时候
就可以使用组合模式
例1
class Component
{
public:
virtual void Operation(){};
virtual void Add(Component *component){}
virtual void Remove(Component *component){}
virtual Component*GetChild(int index){ return nullptr; }
};
class Leaf :public Component
{
virtual void Operation(){};
};
class Compsoite :public Component
{
public:
virtual void Operation(){}
virtual void Add(Component *component)
{
_queue.push_back(component);
}
virtual void Remove(Component *component)
{
auto iter = std::find(_queue.begin(), _queue.end(), component);
if (iter != _queue.end())
{
_queue.erase(iter);
}
}
virtual Component*GetChild(int index)
{
return _queue[index];
}
private:
vector<Component*> _queue;
};
int main(int argc, char *argv[])
{
Compsoite* root = new Compsoite;
auto leaf_1 = new Leaf;
auto leaf_2 = new Leaf;
auto tree_1 = new Compsoite;
root->Add(leaf_1);
root->Add(tree_1);
root->Add(leaf_2);
tree_1->Add(new Leaf);
system("pause");
return 0;
}
例2
Lite2D中的Node类