合成（Composite）模式

一、 合成（Composite）模式

合成模式有时又叫做部分－整体模式（Part-Whole）。合成模式将对象组织到树结构中，可以用来描述整体与部分的关系。合成模式可以使客户端将单纯元素与复合元素同等看待。

二、 合成模式概述

下图所示的类图省略了各个角色的细节。



可以看出，上面的类图结构涉及到三个角色：

抽象构件（Component）角色：这是一个抽象角色，它给参与组合的对象规定一个接口。这个角色给出共有接口及其默认行为。
树叶构件（Leaf）角色：代表参加组合的树叶对象。一个树叶对象没有下级子对象。
树枝构件（Composite）角色：代表参加组合的有子对象的对象，并给出树枝构件对象的行为。

可以看出，Composite类型的对象可以包含其它Component类型的对象。换而言之，Composite类型对象可以含有其它的树枝（Composite）类型或树叶（Leaf）类型的对象。

#ifndef COMPOSITE_H_

#define COMPOSITE_H_

#include <list>

#include <string>

using namespace std;

class Component

{

public:

Component(string astrName){ m_strName = astrName; }

virtual~Component(){}

virtual void Display(int aiDepth) = 0;

protected:

string m_strName;

};

class Leaf : public Component

{

public:

Leaf(string astrName) : Component(astrName){}

virtual void Display(int aiDepth);

};

class Composite : public Component

{

public:

Composite(string astrName) :Component(astrName){}

virtual~Composite();

void Add(Component* apComponent);

void Remove(Component* apComponent);

virtual void Display(int aiDepth);

protected:

list<Component*> m_oChildren;

};

#endif

#include "stdafx.h"

#include "Composite.h"

#include <iostream>

#include <sstream>

#include <algorithm>

void Leaf::Display(int aiDepth)

{

cout<<"Leaf::Display"<<endl;

string astrDestString;

stringstream lostrStream;

lostrStream << aiDepth ;

astrDestString=lostrStream.str();

astrDestString = astrDestString + "-" +m_strName;

cout<< astrDestString<<endl;

}

void Composite::Add(Component* apComponent)

{

m_oChildren.push_back(apComponent);

}

void Composite::Remove(Component* apComponent)

{

//apComponent

//m_oChildren.find();

list<Component*>::iterator itor ;

itor = find(m_oChildren.begin(), m_oChildren.end(), apComponent);

if (itor != m_oChildren.end())

{

m_oChildren.erase(itor);

}

}

Composite::~Composite()

{

Component* lpComponent = NULL;

for (list<Component*>::iterator itor =m_oChildren.begin(); itor != m_oChildren.end(); )

{

lpComponent = *itor;

delete lpComponent;

lpComponent=NULL;

m_oChildren.erase(itor++);

}

}

void Composite::Display(int aiDepth)

{

string astrDestString;

cout<<"Composite::Display"<<endl;

stringstream lostrStream;

lostrStream << aiDepth++ ;

astrDestString=lostrStream.str();

astrDestString = astrDestString + "-" +m_strName;

cout<< astrDestString<<endl;

for (list<Component*>::iterator itor =m_oChildren.begin(); itor != m_oChildren.end(); itor++)

{

(*itor)->Display(aiDepth);

}

}

#include "stdafx.h"

#include "Composite.h"

#include <stdlib.h>

int _tmain(int argc, _TCHAR* argv[])

{

///////root(深度1)----------leafa(深度2)

/////// ----------leafB(深度2)

//////// ----------composite x(深度2)----------leaf Xa(深度3)

//////// ----------leaf XB(深度3)

/////// ----------leaf c(深度2)

Composite *lpRoot = new Composite("root");

lpRoot->Add(new Leaf(" leaf a"));

lpRoot->Add(new Leaf(" leaf B"));

Composite* lpComposite = new Composite("composite x");

lpComposite->Add(new Leaf(" leaf Xa"));

lpComposite->Add(new Leaf(" leaf XB"));

lpRoot->Add(lpComposite);

lpRoot->Add(new Leaf("leaf c"));

Leaf *i = new Leaf("leaf d");

lpRoot->Add(i);

lpRoot->Remove(i);

lpRoot->Display(1);

system("pause");

return 0;

}