大话设计模式-组合模式

需求
设计一个总公司和分公司的OA系统。
实现

public abstract class Company{private String name;public Company(String name){this.name=name;}public Company(){}public String getName() {return name;}public void setName(String name) {this.name=name;}protected abstract void add(Company company);protected abstract void remove(Company company);protected abstract void display(int depth);}

import java.util.*;class ConcreteCompany extends Company{private List<Company> list;public ConcreteCompany(){list=new ArrayList<Company>();}public ConcreteCompany(String name){super(name);list=new ArrayList<Company>(); }@Overrideprotected void add(Company company){// TODO Auto-generated method stublist.add(company);}@Overrideprotected void remove(Company company){// TODO Auto-generated method stublist.remove(company);}@Overrideprotected void display(int depth){// TODO Auto-generated method stubStringBuilder sb=new StringBuilder("");for(int i=0;i<depth;i++){sb.append("-");}System.out.println(new String(sb)+this.getName());for(Company c:list){c.display(depth+2);}}}

public class FinanceDepartment extends Company{public FinanceDepartment(){}public FinanceDepartment(String name){super(name);}@Overrideprotected void add(Company company){// TODO Auto-generated method stub}@Overrideprotected void remove(Company company){// TODO Auto-generated method stub}@Overrideprotected void display(int depth) {// TODO Auto-generated method stubStringBuilder sb=new StringBuilder("");for(int i=0;i<depth;i++){sb.append("-");}System.out.println(new String(sb)+this.getName());}}

public class HRDepartment extends Company{public HRDepartment(){}public HRDepartment(String name){super(name);}@Overrideprotected void add(Company company) {// TODO Auto-generated method stub}@Overrideprotected void remove(Company company) {// TODO Auto-generated method stub}@Overrideprotected void display(int depth){// TODO Auto-generated method stubStringBuilder sb=new StringBuilder("");for(int i=0;i<depth;i++){sb.append("-");}System.out.println(new String(sb)+this.getName());}}

public class Main  {      public static void main(String[] args)      {      Company root=new ConcreteCompany();root.setName("北京总公司");root.add(new HRDepartment("总公司人力资源部"));root.add(new FinanceDepartment("总公司财务部"));Company shandongCom=new ConcreteCompany("山东分公司");shandongCom.add(new HRDepartment("山东分公司人力资源部"));shandongCom.add(new FinanceDepartment("山东分公司账务部"));Company zaozhuangCom=new ConcreteCompany("枣庄办事处");zaozhuangCom.add(new FinanceDepartment("枣庄办事处财务部"));zaozhuangCom.add(new HRDepartment("枣庄办事处人力资源部"));Company jinanCom=new ConcreteCompany("济南办事处");jinanCom.add(new FinanceDepartment("济南办事处财务部"));jinanCom.add(new HRDepartment("济南办事处人力资源部")); shandongCom.add(jinanCom);shandongCom.add(zaozhuangCom);Company huadongCom=new ConcreteCompany("华东分公司");huadongCom.add(new HRDepartment("华东分公司人力资源部"));huadongCom.add(new FinanceDepartment("华东分公司账务部"));Company hangzhouCom=new ConcreteCompany("杭州办事处");hangzhouCom.add(new FinanceDepartment("杭州办事处财务部"));hangzhouCom.add(new HRDepartment("杭州办事处人力资源部"));Company nanjingCom=new ConcreteCompany("南京办事处");nanjingCom.add(new FinanceDepartment("南京办事处财务部"));nanjingCom.add(new HRDepartment("南京办事处人力资源部"));huadongCom.add(hangzhouCom);huadongCom.add(nanjingCom); root.add(shandongCom);root.add(huadongCom);root.display(0);    }  }

组合模式，将对象组合成树形结构以表示部分-整体的层次结构，使得用户对单个对象和组合对象的使用具有一致性。用于对象的部分-整体层次结构，如树形菜单、文件夹菜单、部门组织架构图；也用于需要对用户隐藏组合对象与单个对象的不同时的情况，使得用户统一地使用组合结构中的所有对象。