建造者模式

1. 建造者模式(Builder Pattern) 也叫生成器模式，其定义如下：
   Separate the construction of a complex object from its representation so that the same construction process can create different representations.(将一个复杂对象的构建与他的表示分离，是得同样的构建过程可以创建不同的表示。)
   在建造者模式中，有如下4个角色：

• Product产品类
  通常是实现了模板方法模式，也就是有模板方法和基本方法。
• Builder抽象建造者
  规范产品的组件，一般是由子类实现。例子中的CarBuilder就属于抽象建造者。
• ConcreteBuilder具体建造者
  实现抽象类定义的所有方法，并且返回一个组建好的对象。
• Director导演类
  负责安排已有模块的顺序，然后告诉Builder开始建造，在上面的例子中就是我们的老大，xx公司找到老大，说我要这个或那个类型的车辆模型，然后老大就把命令传递给我，我和我的团队就开始拼命的建造，于是一个项目建设完毕了。
  建造者模式的通用源码也比较简单，先看Product类，通常它是一个组合或继承（如模板方法模式）产生的类

  package com.wzl.fea;
  
  import java.util.ArrayList;
  
  abstract class CarBuilder {
      public abstract void setSequence(ArrayList<String> sequence);
      public abstract CarModel getCarModel();
  }
  
  abstract class CarModel {
      private ArrayList<String> sequence = new ArrayList<String>();
      protected abstract void start();
      protected abstract void stop();
      protected abstract void alarm();
      protected abstract void engineBoom();
  
      final public void run() {
          for (int i = 0; i < this.sequence.size(); ++i) {
              String actionName = this.sequence.get(i);
              if (actionName.equalsIgnoreCase("start")) {
                  this.start();
              }
              else if (actionName.equalsIgnoreCase("stop")) {
                  this.stop();
              }
              else if (actionName.equalsIgnoreCase("alarm")) {
                  this.alarm();
              }
              else if (actionName.equalsIgnoreCase("engine boom")) {
  //如果是engine boom关键字
                  this.engineBoom();
              }
          }
      }
  
      final public void setSequence(ArrayList sequence){
          this.sequence = sequence;
      }
  }
  
  class BenzModel extends CarModel {
      protected void alarm() {
          System.out.println("奔驰车的喇叭声音是这个样子的...");
      }
      protected void engineBoom() {
          System.out.println("奔驰车的引擎是这个声音的...");
      }
      protected void start() {
          System.out.println("奔驰车跑起来是这个样子的...");
      }
      protected void stop() {
          System.out.println("奔驰车应该这样停车...");
      }
  }
  
  class BMWModel extends CarModel {
      protected void alarm() {
          System.out.println("宝马车的喇叭声音是这个样子的...");
      }
      protected void engineBoom() {
          System.out.println("宝马车的引擎是这个声音的...");
      }
      protected void start() {
          System.out.println("宝马车跑起来是这个样子的...");
      }
      protected void stop() {
          System.out.println("宝马车应该这样停车...");
      }
  }
  
  class BenzBuilder extends CarBuilder {
      private BenzModel benz = new BenzModel();
  
      @Override
      public CarModel getCarModel() {
          return this.benz;
      }
  
      @Override
      public void setSequence(ArrayList<String> sequence) {
          this.benz.setSequence(sequence);
      }
  }
  
  class BMWBuilder extends CarBuilder {
      private BMWModel bmw = new BMWModel();
  
      @Override
      public CarModel getCarModel() {
          return this.bmw;
      }
  
      @Override
      public void setSequence(ArrayList<String> sequence) {
          this.bmw.setSequence(sequence);
      }
  }
  
  class CarDirector {
      private ArrayList<String> sequence = new ArrayList<>();
      private BenzBuilder benzBuilder = new BenzBuilder();
      private BMWBuilder bmwBuilder = new BMWBuilder();
  
      public BenzModel getABenzModel(){
          this.sequence.clear();
          this.sequence.add("start");
          this.sequence.add("stop");
          this.benzBuilder.setSequence(this.sequence);
          return (BenzModel)this.benzBuilder.getCarModel();
      }
  
      public BenzModel getBBenzModel(){
          this.sequence.clear();
          this.sequence.add("engine boom");
          this.sequence.add("start");
          this.sequence.add("stop");
          this.benzBuilder.setSequence(this.sequence);
          return (BenzModel)this.benzBuilder.getCarModel();
      }
  
      public BMWModel getCBMWModel(){
          this.sequence.clear();
          this.sequence.add("alarm");
          this.sequence.add("start");
          this.sequence.add("stop");
          this.bmwBuilder.setSequence(this.sequence);
          return (BMWModel)this.bmwBuilder.getCarModel();
      }
  
      public BMWModel getDBMWModel(){
          this.sequence.clear();
          this.sequence.add("start");
          this.bmwBuilder.setSequence(this.sequence);
          return (BMWModel)this.benzBuilder.getCarModel();
      }
  }
  
  
  public class EpCarBuilder {
      public static void main(String[] args) {
          ArrayList<String> sequence = new ArrayList<String>();
          sequence.add("engine boom");
          sequence.add("start");
          sequence.add("stop");
  
          BenzBuilder benzBuilder = new BenzBuilder();
          benzBuilder.setSequence(sequence);
          BenzModel benz = (BenzModel)benzBuilder.getCarModel();
          benz.run();
  
          CarDirector director = new CarDirector();
          //1万辆A类型的奔驰车
          for(int i=0;i<2;i++){
              director.getABenzModel().run();
          }
          //100万辆B类型的奔驰车
          for(int i=0;i<3;i++){
              director.getBBenzModel().run();
          }
          //1000万辆C类型的宝马车
          for(int i=0;i<5;i++){
              director.getCBMWModel().run();
          }
  
  
      }
  }