设计模式（组合模式）

组合模式是为了解决业务中“局部-整体”的关系，这里的局部整体互相嵌套，且具备相同的处理接口。

典型的角色是两个：

component:包含自身抽象列表的类，下例中为Employee;

composite：各个组成部分对外暴露的处理接口，下例中为toString，为单独抽象；

代码如下：

Employee

package com.example;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class Employee {

private String name;
private String deptname;
private List<Employee> subs;

public Employee(String name, String deptname){
this.name = name;
this.deptname = deptname;
subs = new ArrayList<Employee>();
}

public void add(Employee e) {
subs.add(e);
}

public void remove(Employee e) {
for (Iterator<Employee> it = subs.iterator(); it.hasNext();) {
if (((Employee) it.next()).name == e.name) {
it.remove();
}
}
}

//这里的toString，等价于于composite方法
public String toString() {
return ("Employee :[ Name : " + name + ", dept : " + deptname + " ]");
}

public List<Employee> getSubs() {
return subs;
}

}

App 测试类

public class App {

public static void main(String[] args) {
Employee e1 = new Employee("fredric", "dept1");
Employee e2 = new Employee("sinny", "dept2");
Employee e3 = new Employee("baobao", "dept2");
e1.add(e2);
e1.add(e3);
for(Employee emp:e1.getSubs()){
System.out.println(emp);
}
e1.remove(e2);
for(Employee emp:e1.getSubs()){
System.out.println(emp);
}
}
}