组合模式

把一组相似的对象当作一个单一的对象。
将对象组合成树形结构以表示“部分-整体”的层次机构。

被操作的对象，该对象带有该类的对象列表：

import java.util.ArrayList;import java.util.List;public class Employee {   private String name;   private String dept;   private int salary;   private List<Employee> subordinates;   //构造函数   public Employee(String name,String dept, int sal) {      this.name = name;      this.dept = dept;      this.salary = sal;      subordinates = new ArrayList<Employee>();   }   public void add(Employee e) {      subordinates.add(e);   }   public void remove(Employee e) {      subordinates.remove(e);   }   public List<Employee> getSubordinates(){     return subordinates;   }   public String toString(){      return ("Employee :[ Name : "+ name       +", dept : "+ dept + ", salary :"      + salary+" ]");   }   }

public class CompositePatternDemo {   public static void main(String[] args) {      Employee CEO = new Employee("John","CEO", 30000);      Employee headSales = new Employee("Robert","Head Sales", 20000);      Employee headMarketing = new Employee("Michel","Head Marketing", 20000);      Employee clerk1 = new Employee("Laura","Marketing", 10000);      Employee clerk2 = new Employee("Bob","Marketing", 10000);      Employee salesExecutive1 = new Employee("Richard","Sales", 10000);      Employee salesExecutive2 = new Employee("Rob","Sales", 10000);      CEO.add(headSales);      CEO.add(headMarketing);      headSales.add(salesExecutive1);      headSales.add(salesExecutive2);      headMarketing.add(clerk1);      headMarketing.add(clerk2);      //打印该组织的所有员工      System.out.println(CEO);       for (Employee headEmployee : CEO.getSubordinates()) {         System.out.println(headEmployee);         for (Employee employee : headEmployee.getSubordinates()) {            System.out.println(employee);         }      }           }}