设计模式（九）：组合模式

[1. 组合模式的介绍](#1. 组合模式的介绍)
[2. 组合模式的类图](#2. 组合模式的类图)
[3. 组合模式的实现](#3. 组合模式的实现)

1. 组合模式的介绍

组合模式（Composite Pattern）属于结构型模式，是用于把一组相似的对象当作一个单一的对象。

组合模式依据树形结构来组合对象，用来表示部分以及整体层次。这种类型的设计模式它创建了对象组的树形结构。

2. 组合模式的类图

表示一个公司的组织结构，创建一个组织对象，组织对象中包含多个子组织。

3. 组合模式的实现

java 复制代码

package blog;

import java.util.List;

/**
 * 组织结构
 */
public class Organization {
    private String name;

    private List<Organization> organizations;

    public Organization(String name, List<Organization> organizations) {
        this.name = name;
        this.organizations = organizations;
    }

    public void add(Organization organization) {
        organization.add(organization);
    }

    public void remove(Organization organization) {
        organization.remove(organization);
    }

    public List<Organization> getOrganizations() {
        return organizations;
    }
}

java 复制代码

package blog;

import java.util.ArrayList;
import java.util.List;

public class CompositeDemo {
    public static void main(String[] args) {
        Organization organization = new Organization("总裁办", new ArrayList<>());

        Organization sub1 = new Organization("财务部门", new ArrayList<>());

        Organization sub2 = new Organization("业务部门", new ArrayList<>());

        Organization sub3 = new Organization("研发部门", new ArrayList<>());

        Organization sub4 = new Organization("生产部门", new ArrayList<>());

        Organization sub5 = new Organization("客服部门", new ArrayList<>());

        Organization sub11 = new Organization("会计部门", new ArrayList<>());

        Organization sub12 = new Organization("出纳部门", new ArrayList<>());

        organization.getOrganizations().add(sub1);
        organization.getOrganizations().add(sub2);
        organization.getOrganizations().add(sub3);
        organization.getOrganizations().add(sub4);
        organization.getOrganizations().add(sub5);

        sub1.getOrganizations().add(sub11);
        sub1.getOrganizations().add(sub12);

        showOrganization(organization, 0);
    }

    private static void showOrganization(Organization organization, int indentation) {
        for (int i = 0; i < indentation; i++) {
            System.out.print(" ");
        }
        System.out.println(organization.getName());

        List<Organization> organizations = organization.getOrganizations();

        if (!organizations.isEmpty()) {
            organizations.forEach(sub -> {
                showOrganization(sub, indentation + 2);
            });
        }

    }
}