Question

I am learning about the builder pattern, and so far I understood that, it is a great alternative to the commonly patterns used for initialization:

• Telescoping Constructor Pattern

• JavaBean Pattern

The thing is, I don’t really like to remove the getters and setters from the objects in my domain model. I always like to keep them as POJOs. One of the reasons I don’t like it is:
If i don’t use POJOs, then it is not easy to annotate the variables when using ORM frameworks…

So here are my doubts:
-Is it possible to implement the builder pattern without using static inner classes?
-If I have to use the builder pattern by using the inner class, do you think it is correct to keep the getters and the setters?
-I did a little example for practice where I tried to avoid the inner class.
Could you let me what do you think about it?

Product

    public class Product
{
    private String color;
    private int price;

    public Product() {
    }

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        this.color = color;
    }

    public int getPrice() {
        return price;
    }

    public void setPrice(int price) {
        this.price = price;
    }

    public String toString() {
        return getColor() + "\n" + getPrice();
    }    
}

Builder

public class Builder
{
    private Product product;

    public Builder() {
        product = new Product();
    }
    public Builder withColor(String color) {        
        product.setColor(color);
        return this;
    }

     public Builder withPrice(int price) {        
        product.setPrice(price);
        return this;
    }
    public Product build() {
        return product;
    }
}**

Client

public class Client
{

    public static void main(String[] args) {
        System.out.println(new Builder().withColor("Black").withPrice(11).build());
        System.out.println("-----------------------------------------------------");
        System.out.println(new Builder().withColor("Blue").withPrice(12).build());
    }
}

Answer 1

The Builder pattern is useful to create immutable objects and avoid several constructors with optional parameters.

IMO using Builder pattern to build a POJO which can be updated using setters is useless. You only create an additional class.

Depending on the ORM framework used, it might not need the presence of setter method. But only assigning members values through reflection.

Product class:

public final class Product {
    private final String color;
    private final int price;

    public Product(Builder builder) {
        this.color = builder.getColor();
        this.price = builder.getPrice();
    }

    public String getColor() {
        return color;
    }

    public int getPrice() {
        return price;
    }

    public String toString() {
        return getColor() + "\n" + getPrice();
    }    
}

Builder class:

public final class Builder {

    private String color;
    private int price;

    public Builder() {
        // Assign any default values
    }

    public Builder color(String color) {        
        this.color = color;
        return this;
    }

    public Builder price(int price) {        
        this.price = price;
        return this;
    }

    protected String getColor() {
        return color;
    }

    protected int getPrice() {
        return price;
    }

    public Product build() {
        return new Product(this);
    }
}