建造者模式

// 产品
public class Product {
    @Override
    public String toString() {
        return "Product{" +
                "wheel='" + wheel + '\'' +
                ", engine='" + engine + '\'' +
                ", chassis='" + chassis + '\'' +
                '}';
    }
    // 模拟汽车 轮子 发动机 底盘
    private String wheel;
    private String engine;
    private String chassis;
    public String getWheel() {  return wheel;}
    public void setWheel(String wheel) {this.wheel = wheel; }
    public String getEngine() {    return engine;}
    public void setEngine(String engine) { this.engine = engine;}
    public String getChassis() { return chassis; }
    public void setChassis(String chassis) {   this.chassis = chassis; }
}

// 抽象建造者
public interface Builder {
    // 创建组件A
    void buildPartA();
    // 创建组件B
    void buildPartB();
    // 创建组件C
    void buildPartC();
    Product getResult();
}

// 建造者的具体实现
public class ConcreteBuilder implements Builder {
    private Product product;
    public ConcreteBuilder() {
        this.product = new Product();
    }
    @Override
    public void buildPartA() {product.setWheel(new String("米其林轮胎"));  }
    @Override
    public void buildPartB() {product.setEngine(new String("三菱发动机"));  }
    @Override
    public void buildPartC() {product.setChassis(new String("宝马底盘"));   }
    @Override
    public Product getResult() {return product; }
}

// 指挥者
// 客户端直接利用指挥者创建对象, 给指挥者传入一个建造者实例
public class Diector {
    private Builder builder;
    public void setBuilder(Builder builder) {
        this.builder = builder;
    }
    public Diector(Builder builder){
        this.builder=builder;
    }
    public Product construct(){
        builder.buildPartA();
        builder.buildPartB();
        builder.buildPartC();
        return builder.getResult();
    }
}