设计模式之一致性_Composite组合模式_容器和内容的一致性(对象包含对象)

向右看齐 2024-04-17 05:45 23阅读 0赞

## 前言 ##

#### [博主github][github] ####

#### [博主个人博客http://blog.healerjean.com][http_blog.healerjean.com] ####

## 1、解释 ##

**组合模式** 一般用来描述 *整体* 与 *部分* 的关系，它将对象组织到树形结构中，

最顶层的节点称为 **根节点**，根节点下面可以包含 **树枝节点** 和 **叶子节点**，树枝节点下面又可以包含 **树枝节点** 和 **叶子节点**。如下图所示：

\[外链图片转存失败(img-uL1Lf563-1566550768885)(D:\\study\\HealerJean.github.io\\blogImages\\1565775856439.png)\]

## 2、实例代码 ##

一个公司中从上到下有分级，那其实就是一个树形结构

### 2.1、员工表 ###

package com.hlj.moudle.design.D05_一致性;
    
    import java.util.ArrayList;
    import java.util.List;
    
    
    public class Employee { 
        private String name;
        private String dept;
        private int salary;
        private List<Employee> subordinates;
    
    
        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;
        }
    
        @Override
        public String toString() { 
            return ("Employee :[ Name : " + name
                    + ", dept : " + dept + ", salary :"
                    + salary + " ]");
        }
    }

### 2.2、测试 容器和内容 ###

package com.hlj.moudle.design.D05_一致性;
    
    /** * @author HealerJean * @ClassName Main * @date 2019/8/14 17:50. * @Description */
    public class Main { 
    
        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);
    
            headSales.add(salesExecutive1);
            headSales.add(salesExecutive2);
    
            headMarketing.add(clerk1);
            headMarketing.add(clerk2);
    
            CEO.add(headSales);
            CEO.add(headMarketing);
    
    
            //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);
                }
            }
        }
    }

## 3、总结 ##

**所谓组合模式，其实说的是对象包含对象的问题，通过组合的方式（在对象内部引用对象）来进行布局**

![ContactAuthor][]

[github]: https://github.com/HealerJean
[http_blog.healerjean.com]: http://HealerJean.github.io
[ContactAuthor]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/11/b24ed6008d904baf87e3581eb9d79611.png