Builder.md

Builder

Description

Builder pattern allows you to construct complex objects step by step. It separates the construction of a complex object from its representation. This pattern is particularly useful when creating complex objects with numerous configurations. It provides better control over the construction process. The Builder pattern is often used to construct products that have a large number of optional parameters.

Java Code Example

class Car {
    private String engine;
    private String body;
    
    public void setEngine(String engine) { this.engine = engine; }
    public void setBody(String body) { this.body = body; }
    public String toString() { return "Car with " + this.engine + " engine and " + this.body + " body."; }
}

interface CarBuilder {
    void buildEngine();
    void buildBody();
    Car getCar();
}

class SportsCarBuilder implements CarBuilder {
    private Car car = new Car();
    
    public void buildEngine() { car.setEngine("V8 Engine"); }
    public void buildBody() { car.setBody("Sporty Body"); }
    public Car getCar() { return car; }
}

class Director {
    private CarBuilder builder;
    public Director(CarBuilder builder) { this.builder = builder; }
    public Car construct() {
        builder.buildEngine();
        builder.buildBody();
        return builder.getCar();
    }
}

public class BuilderPattern {
    public static void main(String[] args) {
        CarBuilder builder = new SportsCarBuilder();
        Director director = new Director(builder);
        Car car = director.construct();
        System.out.println(car);
    }
}