Hands-On Object-Oriented Programming with Kotlin

Builder

The Builder pattern is useful when we need to initialize many fields during new object creation. According to this pattern, instead of using a constructor with a lot of parameters, we can create a nested class that collects all passed arguments and constructs a new object. Let's look at the typical implementation of this pattern in a classic Java way. Let's imagine that we need to cook a burger. For this, we need to define classes of ingredients:

class Meatclass Cheeseclass Ketchupclass Bun

We also need to define the Burger class, which encapsulates all ingredients:

class Burger {    private val meat: Meat    private val cheese: Cheese    private val ketchup: Ketchup    private val topBun: Bun    private val bottomBun: Bun    private constructor(meat ...