Java设计模式之建造者模式详解

// 产品类
public class Product {
    private String partA;
    private String partB;
    private String partC;
    public void setPartA(String partA) {
        this.partA = partA;
    }
    public void setPartB(String partB) {
        this.partB = partB;
    }
    public void setPartC(String partC) {
        this.partC = partC;
    }
    public void show() {
        System.out.println("产品组成： PartA - " + partA + ", PartB - " + partB + ", PartC - " + partC);
    }
}
// 抽象建造者
public interface Builder {
    void buildPartA();
    void buildPartB();
    void buildPartC();
    Product getResult();
}
// 具体建造者A
public class ConcreteBuilderA implements Builder {
    private Product product = new Product();
    @Override
    public void buildPartA() {
        product.setPartA("A1");
    }
    @Override
    public void buildPartB() {
        product.setPartB("B1");
    }
    @Override
    public void buildPartC() {
        product.setPartC("C1");
    }
    @Override
    public Product getResult() {
        return product;
    }
}
// 具体建造者B
public class ConcreteBuilderB implements Builder {
    private Product product = new Product();
    @Override
    public void buildPartA() {
        product.setPartA("A2");
    }
    @Override
    public void buildPartB() {
        product.setPartB("B2");
    }
    @Override
    public void buildPartC() {
        product.setPartC("C2");
    }
    @Override
    public Product getResult() {
        return product;
    }
}
// 导演类
public class Director {
    public Product construct(Builder builder) {
        builder.buildPartA();
        builder.buildPartB();
        builder.buildPartC();
        return builder.getResult();
    }
}

// 电子邮件产品类
public class Email {
    private String subject;
    private String body;
    private String attachment;
    // 省略getter和setter
}
// 电子邮件建造者接口
public interface EmailBuilder {
    void buildSubject();
    void buildBody();
    void buildAttachment();
    Email getResult();
}
// 具体电子邮件建造者A
public class WelcomeEmailBuilder implements EmailBuilder {
    private Email email = new Email();
    @Override
    public void buildSubject() {
        email.setSubject("欢迎邮件");
    }
    @Override
    public void buildBody() {
        email.setBody("欢迎加入我们的大家庭！");
    }
    @Override
    public void buildAttachment() {
        // 欢迎邮件没有附件
    }
    @Override
    public Email getResult() {
        return email;
    }
}