[Java] 详解java构建者模式Builder

package com.example.myjavademo;
 
/**
 * 计算机的组装过程较为复杂，并且组装过程不固定，为了易于理解，我们把计算机组装过程简化为
 * 构建主机、设置操作系统、设置显示器3步，然后通过directer和具体builder来构建计算机对象
 *
 */
public class builderdesigndemo {
 public static void main(string []args){
 //方式一
 builder builder=new macbookbuilder();
 director director=new director(builder);
 director.construct("intel","aoc");
 system.out.println(builder.create().tostring());
 
 
 //方式2
 system.out.println(new macbookbuilder().
  buildboard("intel").builddisplay("aoc").create().tostring());
 
 
 }
}
 
/**
 * 计算机抽象类，即product角色
 */
abstract class computer{
 
 protected string mboard;
 protected string mdisplay;
 protected string mos;
 protected computer(){
 
 }
 public void setboard(string board){//具体什么实现进行了隐藏
 
 this.mboard=board;
 }
 public void setdisplay(string display){//具体什么实现进行了隐藏
 this.mdisplay=display;
 }
 public abstract void setos();
 
 @override
 public string tostring() {
 return "computer:="+mboard+",="+mos+",="+mdisplay;
 }
}
 
/**
 * 具体的computer类
 */
 
class macbook extends computer{
 protected macbook(){};
 @override
 public void setos() {
 mos="mac os x";
 }
}
 
/**
 * 抽象builder类
 */
abstract class builder{
 //设置主机
 public abstract builder buildboard(string board);
 //设置操作系统
 public abstract builder buildos();
 //设置显示器
 public abstract builder builddisplay(string display);
 //创建computer
 public abstract computer create();
}
 
/**
 * 具体builder类，macbookbuilder
 */
class macbookbuilder extends builder{
 private computer computer=new macbook();
 
 @override
 public builder buildboard(string board) {
 computer.setboard(board);
 return this;
 }
 
 @override
 public builder buildos() {
 computer.setos();
 return this;
 }
 
 @override
 public builder builddisplay(string display) {
 computer.setdisplay(display);
 return this;
 }
 
 @override
 public computer create() {//mac的操作系统肯定是mac os的；这部分对外部隐藏
 computer.setos();
 return computer;
 }
}
 
/**
 * director类，负责构建computer
 */
class director{
 builder builder=null;
 
 public director(builder builder) {
 this.builder = builder;
 }
 /**
 * 构建对象
 */
 public void construct(string board,string display){
 builder.buildboard(board);
 builder.builddisplay(display);
 
 }
}