设计模式C++描述----11.组合(Composite)模式 (一)

上一篇：http://www.2cto.com/kf/201205/132469.html

一. 举例

这个例子是书上的，假设有一个公司的组结结构如下：

它的结构很像一棵树，其中人力资源部和财务部是没有子结点的，具体公司才有子结点。

而且最关健的是，它的每一层结构很相似。

代码实现如下：
[cpp] view plaincopyprint //公司类，提供接口
class Company
{
public:
Company(string name)
{
m_name = name;
}

virtual ~Company()
{}

virtual void Add(Company *pCom)
{}

virtual void Display(int depth)
{}

protected:
string m_name;
};

//具体公司
class ConcreteCompany : public Company
{
public:
ConcreteCompany(string name): Company(name)
{}

virtual ~ConcreteCompany()
{}

//增加子树或叶子
void Add(Company *pCom)
{
m_listCompany.push_back(pCom);
}

//显示
void Display(int depth)
{
for(int i = 0;i < depth; i++)
{
cout<<"-";

}

cout<< m_name << endl;

list::iterator iter = m_listCompany.begin();

for(; iter != m_listCompany.end(); iter++) //显示下层结点
{
(*iter)->Display(depth + 2);
}
}

private:
list m_listCompany;
};

//具体的部门，财务部
class FinanceDepartment : public Company
{
public:
FinanceDepartment(string name):Company(name)
{}

virtual ~FinanceDepartment()
{}

//只需显示，无限添加函数，因为已是叶结点
virtual void Display(int depth)
{
for(int i = 0; i < depth; i++)
cout<<"-";

cout<< m_name << endl;
}
};

//具体的部门，人力资源部
class HRDepartment :public Company
{
public:
HRDepartment(string name):Company(name)
{}

virtual ~HRDepartment()
{}

//只需显示，无限添加函数，因为已是叶结点
virtual void Display(int depth)
{
for(int i = 0; i < depth; i++)
{
cout<<"-";
}
cout<< m_name << endl;
}
};

//////////////////////////////////////////////////////////////////////////
//测试代码
int main()
{
Company *root = new ConcreteCompany("总公司");
Company *leaf1=new FinanceDepartment("财务部");
Company *leaf2=new HRDepartment("人力资源部");
root->Add(leaf1);
root->Add(leaf2);

//华东分公司
Company *mid1 = new ConcreteCompany("华东分公司");
Company *leaf3=new FinanceDepartment("华东分公司财务部");
Company *leaf4=new HRDepartment("华东分公司人力资源部");
mid1->Add(leaf3);
mid1->Add(leaf4);
root->Add(mid1);

//南京办事处
Company *mid2=new ConcreteCompany("南京办事处");
FinanceDepartment *leaf5=new FinanceDepartment("南京办事处财务部");
HRDepartment *leaf6=new HRDepartment("南京办事处人力资源部");
mid2->Add(leaf5);
mid2->Add(leaf6);
root->Add(mid2);

//杭州办事处
Company *mid3=new ConcreteCompany("杭州办事处");
FinanceDepartment *leaf7=new FinanceDepartment("杭州办事处财务部");
HRDepartment *leaf8=new HRDepartment("杭州办事处人力资源部");
mid3->Add(leaf7);
mid3->Add(leaf8);
mid2->Add(mid3);

root->Display(0);

delete leaf1;
delete leaf2;
delete leaf3;
delete leaf4;
delete leaf5;
delete leaf6;
delete leaf7;
delete leaf8;
delete mid1;
delete mid2;
delete root;

return 0;
}
//公司类，提供接口
class Company
{
public:
Company(string name)
{
m_name = name;
}

virtual ~Company()
{}

virtual void Add(Company *pCom)
{}

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