组合模式学习笔记

最新推荐文章于 2025-02-18 19:00:00 发布

原创最新推荐文章于 2025-02-18 19:00:00 发布 · 191 阅读

1 ·

CC 4.0 BY-SA版权

Kotlin 同时被 2 个专栏收录

32 篇文章

订阅专栏

Design Patterns

17 篇文章

订阅专栏

学校包含若干个学院，学院又包含若干个专业，其中就是组合关系（树形结构）。直接上代码

1. 抽象基类

import java.lang.UnsupportedOperationException

abstract class AbstractOrganizationComponent {
    protected var name: String
    protected var description: String

    constructor(name: String, description: String) {
        this.name = name
        this.description = description
    }

    open fun addChild(component: AbstractOrganizationComponent) {
        throw UnsupportedOperationException()
    }

    open fun removeChild(component: AbstractOrganizationComponent) {
        throw UnsupportedOperationException()
    }

    abstract fun printIntroduce()
}

2. 专业（叶子节点）

import android.util.Log

class Department(name: String, description: String) :
    AbstractOrganizationComponent(name, description) {

    override fun printIntroduce() {
        //println("${super.name} :  ${super.description}")
        Log.d("Department", "$name :  $description")
    }
}

3. 学院（组合节点）

import android.util.Log

class College(name: String, description: String) :
    AbstractOrganizationComponent(name, description) {
    private var departmentsList = mutableListOf<AbstractOrganizationComponent>()

    override fun addChild(component: AbstractOrganizationComponent){
        departmentsList.add(component)
    }

    override fun removeChild(component: AbstractOrganizationComponent) {
        departmentsList.remove(component)
    }

    override fun printIntroduce() {
        //println("========================${super.name}, ${super.description} ===========")
        Log.d("College", "========================$name, $description ===========")
        for (i in departmentsList.indices) {
            departmentsList[i].printIntroduce()
        }
    }
}

4. 学校（组合节点）

import android.util.Log

class University(name: String, description: String) :
    AbstractOrganizationComponent(name, description) {
    private var collegesList = mutableListOf<AbstractOrganizationComponent>()

    override fun addChild(component: AbstractOrganizationComponent){
        collegesList.add(component)
    }

    override fun removeChild(component: AbstractOrganizationComponent) {
        collegesList.remove(component)
    }

    override fun printIntroduce() {
        //println("========================$name, $description ===========")
        Log.d("University", "========================$name, $description ===========")
        for (i in collegesList.indices) {
            collegesList[i].printIntroduce()
        }
    }
}

5.测试代码

    // *********************** Composite design pattern ****************************
    @Test
    fun testComposite() {
        var softWareDepartment = Department("软件工程专业", "这个专业就业前景很好")
        var networkDepartment = Department("网络工程专业", "这个专业也不错")
        var computerCollege = College("计算机学院", "这是个一流学院")
        computerCollege.addChild(softWareDepartment)
        computerCollege.addChild(networkDepartment)

        var communicationDepartment = Department("通信工程专业", "这个专业有点难学")
        var electronicDepartment = Department("电子工程专业", "这个专业容易一点")
        var infoCollege = College("信息工程学院", "这是个技术性很强的学院")
        infoCollege.addChild(communicationDepartment)
        infoCollege.addChild(electronicDepartment)

        var qinghuaUniversity = University("清华大学", "这是一所顶级大学")
        qinghuaUniversity.addChild(computerCollege)
        qinghuaUniversity.addChild(infoCollege)
        qinghuaUniversity.printIntroduce()
    }
    // *********************** Composite design pattern ****************************

6. 运行结果

09-15 21:59:59.566 D    University:        ========================清华大学, 这是一所顶级大学 =========== 
09-15 21:59:59.566 D    College            : ========================计算机学院, 这是个一流学院 =========== 
09-15 21:59:59.567 D    Department:        软件工程专业 :  这个专业就业前景很好 
09-15 21:59:59.567 D    Department:        网络工程专业 :  这个专业也不错 
09-15 21:59:59.567 D    College            : ========================信息工程学院, 这是个技术性很强的学院 =========== 
09-15 21:59:59.567 D    Department:        通信工程专业 :  这个专业有点难学 
09-15 21:59:59.567 D    Department:        电子工程专业 :  这个专业容易一点