【结构型】组合模式
定义
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定义：将对象组合成树形结构以表示‘部分-整体’的 层次结构。组合模式使得用户对单个对象和组合对象的使用具有一致性。
代理模式几个角色：
1.抽象构件角色：组合中对象声明接口，在适当情况下，实现所有类共有的默认行为。声明一个接口用于访问和管理子部件
2.树叶构件角色：在组合树中表示叶节点对象，叶节点没有子节点
3.树枝构件角色：定义有子部件的那些部件的行为。存储子部件，在抽象构件角色中实现与子部件有关的操作
UML图
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_ _ _ _ _ _ _ _ _ _
| | | |
| Client |----→| Component |←------------┐
|_ _ _ _| |_ _ _ _ _ _| |
↑ |
| |
| |
┌----------------┐ |
| | |
| | children|
| | |
_ _ _| _ _ _ _ |_ _ _ _ _ |
| Leaf | | Composite |--┘
|_ _ _ _ _ | |_ _ _ _ __ _ _|
代码
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abstract class CompanyGroup{
protected String name;
protected int employeeNum;
public void setLeaderName(String name, int employeeNum){
this.name = name;
this.employeeNum = employeeNum;
}
public abstract void addSubCompany(CompanyGroup companyGroup);
public abstract void employeeNum();
}
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public class company extends CompanyGroup{
public company(String name, int num){
super(name,num);
}
@override
public void addSubCompany(CompanyGroup companyGroup){
//Nothing do do.
}
@override
public void employeeNum(){
System.out.println(this.name+" have "+this.employeeNum+" employees.");
}
}
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public class CompanyCN extends CompanyGroup{
private List<CompanyGroup> companyList = new ArrayList<CompanyGroup>();
public CompanyCN(String name, int num){
super(name,num);
}
@override
public void addSubCompany(CompanyGroup companyGroup){
companyList.add(companyGroup);
}
@override
public void employeeNum(){
for(CompanyGroup company in companyList){
company.employeeNum();
}
System.out.println(this.name+" have "+this.employeeNum+" employees.");
}
}
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public class Client{
public static void main(String[] args){
CompanyGroup companyCN = new CompanyCN("ChinaCN",100);
companyCN.add(new Company("bj",50);
companyCN.add(new Company("sh",50);
companyCN.employeeNum();
}
}
运行结果：
bj have 50 employees.
sh have 50 employees.
ChinaCN have 100 employees.