Java设计模式 - 组合模式

组合模式是结构型模式，因为它创建了一组对象的树结构。

组合模式将一组对象视为单个对象。

组合模式使用一个类来表示树结构。

在组合模式中，我们创建一个包含自己对象的类的组。

例子

以下代码使用Employee类来演示组合模式。

import java.util.ArrayList;
import java.util.List;class Employee {private String name;private String title;private List<Employee> subordinates;public Employee(String name,String title) {this.name = name;this.title = title;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 : "+ title +subordinates +" ]";}   
}public class Main {public static void main(String[] args) {Employee CEO = new Employee("John","CEO");Employee headSales = new Employee("Rob","Sales");Employee headMarketing = new Employee("Mike","Marketing");Employee programmer1 = new Employee("Lili","Programmer");Employee programmer2 = new Employee("Bob","Programmer");Employee tester1 = new Employee("Jack","Tester");Employee tester2 = new Employee("Tom","Tester");CEO.add(headSales);CEO.add(headMarketing);headSales.add(tester1);headSales.add(tester2);headMarketing.add(programmer1);headMarketing.add(programmer2);//print all employees of the organizationSystem.out.println(CEO); for (Employee headEmployee : CEO.getSubordinates()) {System.out.println(headEmployee);for (Employee employee : headEmployee.getSubordinates()) {System.out.println(employee);}}    }
}

上面的代码生成以下结果。