设计模式C++学习笔记之十五（Composite组合模式）

15.1.解释

概念：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的使用具有一致性。

main()，客户

CCorpNode，抽象基类，实现基本信息

CBranchNode，树枝节点，实现Addordinate()函数和GetSubordinate()函数

CLeafNode，叶子节点，IsLeaf属性总是“true”

说明：组合模式主要是实现在CBranchNode对象里增加对其它对象的数组，如vector<CCorpNode*>，数组里可以存放CBranchNode和CLeafNode对象。这样方便进行遍历操作。

注意：组合模式有透明组合模式和安全组合模式。透明组合模式是将Addordinate和GetSubordinate这两个函数也抽象到CCorpNode基类里，这增加了操作叶子节点的难度，更易出现逻辑问题。所以尽量使用安全模式。

这个简单了，可以想像一下TreeView和TreeNode基本上是这个意思了，将很多数据组织在一块。

看代码：

//CorpNode.h

#pragma once

#include <iostream>

using std::string;

class CCorpNode

{

public:

CCorpNode();

CCorpNode(string _name, string _pos, int _salary);

virtual ~CCorpNode(void);

virtual string GetInfo();

void SetParent(CCorpNode *_pParent);

CCorpNode * GetParent();

virtual bool IsLeaf() = 0;

private:

string m_name;

string m_position;

int m_salary;

protected:

bool m_isLeaf;

CCorpNode *m_pParent;

};

//CorpNode.cpp

#include "StdAfx.h"

#include "CorpNode.h"

#include "..\CommonDeclare\Convert.h"

CCorpNode::CCorpNode(void)

{

m_name = "";

m_position = "";

m_salary = 0;

}

CCorpNode::CCorpNode(string _name, string _pos, int _salary) : m_name(_name), m_position(_pos), m_salary(_salary)

{

}

CCorpNode::~CCorpNode(void)

{

}

string CCorpNode::GetInfo()

{

string info = "";

info.append("姓名：");

info.append(this->m_name);

info.append("\t职位：");

info.append(this->m_position);

info.append("\t薪水：");

info.append(CConvert::ToString(this->m_salary));

return info;

}

void CCorpNode::SetParent( CCorpNode *_parent )

{

this->m_pParent = _parent;

}

CCorpNode * CCorpNode::GetParent()

{

return this->m_pParent;

}

//BranchNode.h

#pragma once

#include "corpnode.h"

#include "CorpNode.h"

#include <vector>

#include <iostream>

using std::vector;

using std::string;

class CBranchNode :

public CCorpNode

{

public:

CBranchNode(void);

CBranchNode(string name, string pos, int salary);

~CBranchNode(void);

void Add(CCorpNode *pcorpNode);

vector<CCorpNode*> GetSubordinateInfo();

bool IsLeaf();

private:

vector<CCorpNode*> m_subordinateList;

};

//BranchNode.cpp

#include "StdAfx.h"

#include "BranchNode.h"

CBranchNode::CBranchNode(void)

{

m_isLeaf = false;

}

CBranchNode::CBranchNode( string name, string pos, int salary ) : CCorpNode(name, pos, salary)

{

m_isLeaf = false;

}

CBranchNode::~CBranchNode(void)

{

}

void CBranchNode::Add( CCorpNode *pcorpNode )

{

pcorpNode->SetParent(this);

m_subordinateList.push_back(pcorpNode);

}

vector<CCorpNode*> CBranchNode::GetSubordinateInfo()

{

return this->m_subordinateList;

}

bool CBranchNode::IsLeaf()

{

return m_isLeaf;

}

//LeafNode.h

#pragma once

#include "corpnode.h"

class CLeafNode :

public CCorpNode

{

public:

CLeafNode(void);

CLeafNode(string name, string pos, int salary);

~CLeafNode(void);

bool IsLeaf();

};

//LeafNode.cpp

#include "StdAfx.h"

#include "LeafNode.h"

CLeafNode::CLeafNode(void)

{

m_isLeaf = true;

}

CLeafNode::CLeafNode( string name, string pos, int salary ) : CCorpNode(name, pos, salary)

{

m_isLeaf = true;

}

CLeafNode::~CLeafNode(void)

{

}

bool CLeafNode::IsLeaf()

{

return m_isLeaf;

}



曾经开发过一款Gantt图的控件，采用的就是这种模式，有GanttView和GanttNode两个类，IGanttNode一个接口，GanttScale标尺类。GanttView负责显示，GanttNode是实现类，只有一个GanttNode类来实现数据的组合，IGanttNode指示了一个IGanttNodeCollection属性来记录所有下级结点的集合。算是实践中的一个应用吧。