设计模式读书笔记：Composite（组合）

2015-07-10 16:01:01

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意图：

将对象组合成树形结构以表示“部分-整体”的层次结构。Composite使得用户对单个对象和组合对象的使用具有一致性。

结构图：来自 《23种设计模式 - 郗晓勇》

实现：https://github.com/panshiqu/patterns/tree/master/Composite

Component

#include <iostream>

namespace NS_COMPOSITE {

class Component {
public:
	Component(std::string name) : _name(name) {}
	virtual ~Component() {}
	virtual void operation(void)
	{
		std::cout << _name << std::endl;
	}
	virtual void add(Component *component) {}
	virtual void remove(Component *component) {}

private:
	std::string _name;
};

} /* namespace NS_COMPOSITE */

Composite

#include "Component.h"
#include <list>

namespace NS_COMPOSITE {

class Composite : public Component
{
public:
	Composite(std::string name) : Component(name) {}
	virtual ~Composite() {}
	virtual void operation(void)
	{
		Component::operation();
		std::list<Component *>::iterator itr = _components.begin();
		for (; itr != _components.end(); itr++)
		{
			(*itr)->operation();
		}
	}
	virtual void add(Component *component)
	{
		_components.push_back(component);
	}
	virtual void remove(Component *component)
	{
		// do remove
	}

private:
	std::list<Component *> _components;
};

} /* namespace NS_COMPOSITE */

Leaf

#include "Component.h"

namespace NS_COMPOSITE {

class Leaf : public Component
{
public:
	Leaf(std::string name) : Component(name) {}
	virtual ~Leaf() {}
	virtual void operation(void)
	{
		Component::operation();
	}
};

} /* namespace NS_COMPOSITE */

main

#include "Composite/Composite.h"
#include "Composite/Leaf.h"
using namespace NS_COMPOSITE;
int main(void)
{
	Composite c1("c1");
	Leaf l1("l1");
	Composite c2("c2");
	c1.add(&l1);
	c1.add(&c2);
	Leaf l2("l2");
	c2.add(&l2);
	c1.operation();
}

附加：