抽象根節(jié)點(diǎn)（Component）：定義系統(tǒng)各層次對(duì)象的共有方法和屬性，可以預(yù)定義一些默認(rèn)行為和屬性
樹(shù)枝節(jié)點(diǎn)（Composite）：定義樹(shù)枝節(jié)點(diǎn)的行為，存儲(chǔ)子節(jié)點(diǎn)，組合樹(shù)枝節(jié)點(diǎn)和葉子節(jié)點(diǎn)形成一個(gè)樹(shù)形結(jié)構(gòu)
葉子節(jié)點(diǎn)（Leaf）：葉子節(jié)點(diǎn)對(duì)象，其下再無(wú)分支，是系統(tǒng)層次遍歷的最小單位

3.組合模式解決的問(wèn)題

1）組合模式解決這樣的問(wèn)題，當(dāng)我們要處理的對(duì)象可以生成一顆樹(shù)形結(jié)構(gòu)，而我們要對(duì)樹(shù)上的節(jié)點(diǎn)和葉子進(jìn)行操作時(shí)，它能夠提供一致的方式，而不用考慮它是節(jié)點(diǎn)還是葉子

2）對(duì)應(yīng)的示意圖

4.組合模式解決學(xué)校院系展示

1）應(yīng)用實(shí)例要求

編寫(xiě)程序展示一個(gè)學(xué)校院系結(jié)構(gòu)：需求是這樣的，要在一個(gè)頁(yè)面中展示出學(xué)校的院系組成，一個(gè)學(xué)校有多個(gè)學(xué)院，一個(gè)學(xué)院有多個(gè)系

2）思路分析和圖解（類(lèi)圖）

3）代碼實(shí)現(xiàn)

Component組合對(duì)象聲明接口

package com.zte;
public abstract class OrganizationComponent {
    private String name;// 名字
    private String des;// 說(shuō)明
    public String getName() {
        return name;
    }
    public String getDes() {
        return des;
    }
    protected void add(OrganizationComponent organizationComponent) {
        // 默認(rèn)實(shí)現(xiàn)
        throw new UnsupportedOperationException();
    }
    protected void remove(OrganizationComponent organizationComponent) {
        // 默認(rèn)實(shí)現(xiàn)
        throw new UnsupportedOperationException();
    }
    // 構(gòu)造器
    public OrganizationComponent(String name, String des) {
        this.name = name;
        this.des = des;
    }
    // 方法print，抽象方法
    protected abstract void print();
}

Composite非葉子節(jié)點(diǎn)

package com.zte;
import java.util.ArrayList;
import java.util.List;
// University 就是 Composite，可以管理College
public class University extends OrganizationComponent {
    List<OrganizationComponent> organizationComponentList = new ArrayList<>();
    // 構(gòu)造器
    public University(String name, String des) {
        super(name, des);
    }
    //重寫(xiě)add
    @Override
    protected void add(OrganizationComponent organizationComponent) {
        organizationComponentList.add(organizationComponent);
    }
    // 重寫(xiě)remove
    @Override
    protected void remove(OrganizationComponent organizationComponent) {
        organizationComponent.remove(organizationComponent);
    }
    @Override
    protected void print() {
        System.out.println("==========" + getName() + "=========");
        for (OrganizationComponent organizationComponent : organizationComponentList) {
            organizationComponent.print();
        }
    }
    @Override
    public String getName() {
        return super.getName();
    }
    @Override
    public String getDes() {
        return super.getDes();
    }
}

Composite非葉子節(jié)點(diǎn)

package com.zte;
import java.util.ArrayList;
import java.util.List;
public class College extends OrganizationComponent {
    // list中存放department
    List<OrganizationComponent> organizationComponentList = new ArrayList<>();
    public College(String name, String des) {
        super(name, des);
    }
    //重寫(xiě)add
    @Override
    protected void add(OrganizationComponent organizationComponent) {
        organizationComponentList.add(organizationComponent);
    }
    // 重寫(xiě)remove
    @Override
    protected void remove(OrganizationComponent organizationComponent) {
        organizationComponent.remove(organizationComponent);
    }
    @Override
    protected void print() {
        System.out.println("==========" + getName() + "=========");
        for (OrganizationComponent organizationComponent : organizationComponentList) {
            organizationComponent.print();
        }
    }
    @Override
    public String getName() {
        return super.getName();
    }
    @Override
    public String getDes() {
        return super.getDes();
    }
}

Leaf葉子節(jié)點(diǎn)

package com.zte;
public class Department extends OrganizationComponent {
    public Department(String name, String des) {
        super(name, des);
    }
    // add和remove方法就不需要再寫(xiě)了
    @Override
    protected void print() {
        System.out.println("===========" + getName() + "=========");
    }
    @Override
    public String getName() {
        return super.getName();
    }
    @Override
    public String getDes() {
        return super.getDes();
    }
}

package com.zte;
public class Client {
    public static void main(String[] args) {
        // 創(chuàng)建大學(xué)
        OrganizationComponent university = new University("清華大學(xué)", "中國(guó)最好的大學(xué)");
        // 創(chuàng)建學(xué)院
        OrganizationComponent college1 = new College("計(jì)算機(jī)學(xué)院", "計(jì)算機(jī)學(xué)院");
        OrganizationComponent college2 = new College("信息工程學(xué)院", "信息工程學(xué)院");
        // 創(chuàng)建各個(gè)學(xué)院下面的系
        college1.add(new Department("軟件工程", "軟件工程"));
        college1.add(new Department("網(wǎng)絡(luò)工程", "網(wǎng)絡(luò)工程"));
        college1.add(new Department("計(jì)算機(jī)科學(xué)與技術(shù)", "老牌專(zhuān)業(yè)"));
        college2.add(new Department("通信工程", "通信工程"));
        college2.add(new Department("信息工程", "信息工程"));
        // 將學(xué)院添加到學(xué)校中
        university.add(college1);
        university.add(college2);
        // 打印大學(xué)底下的所有院系
        university.print();
        // 打印學(xué)院底下的所有系
        college1.print();
    }
}