【java设计模式】【创建模式Creational Pattern】建造模式Builder Pattern

package com.tn.pattern;

public class Client {
    public static void main(String[] args) {
        Director director=Director.getInstance();
        director.construct(new ConcreteBuilder1());        
        director.construct(new ConcreteBuilder2());
    }
}

class Director{
    static Director director;
    private Director(){}
    public static Director getInstance(){
        if(director==null)
            director=new Director();
        return director;
    }
    public void construct(Builder builder){
        builder.buildPart1();
        builder.buildPart2();
    }
}

interface Builder{
    void buildPart1();
    void buildPart2();
    Product retrieveResult();
}

class ConcreteBuilder1 implements Builder{
    Product product;
    @Override
    public void buildPart1() {
        System.out.println("ConcreteBuilder1.buildPart1()");
        product=new Product1();
    }
    
    @Override
    public void buildPart2() {}
    
    @Override
    public Product retrieveResult() {
        return product;
    }
}

class ConcreteBuilder2 implements Builder{
    Product product;
    @Override
    public void buildPart1() {}
    
    @Override
    public void buildPart2() {
        System.out.println("ConcreteBuilder2.buildPart2()");
        product=new Product2();
    }
    
    @Override
    public Product retrieveResult() {
        return product;
    }
}

interface Product{}

class Product1 implements Product{
    public Product1(){
        System.out.println("Product1.Product1()");
    }
}

class Product2 implements Product{
    public Product2(){
        System.out.println("Product2.Product2()");
    }
}