Simple Factory

Define a class that encapsulates object creation.

Creates an object without exposing the instantiation logic to the client.

Refers the newly created object using a common interface.

simple factory

The Simple Factory isn’t actually a design pattern; It’s more of a programming idiom.

Simple Factory can be defined as a static method and is called static factory. By defining as static method we don’t need to instantiate an object to make use of create method. But the drawback is that we can’t subclass and change the behaviour of the create method;

Example

simple factory example

Code (Java)

public class SimplePizzaFactory {
   public Pizza createPizza(String type) {
      Pizza pizza  = null;
      switch(type){
      case "cheese" :
         pizza = new CheesePizza();
         break;
      case "pepperoni" :
         pizza = new PepperoniPizza();
         break;
      case "veggie" :
         pizza = new VeggiePizza();
         break;
      }
      return pizza;
   }
}

public class PizzaStore {
   SimplePizzaFactory factory;
   
   public PizzaStore(SimplePizzaFactory factory){
      this.factory = factory;
   }
   
   public Pizza orderPizza(String type){
      Pizza pizza;
      
      pizza = factory.createPizza(type);
      
      pizza.prepare();
      pizza.bake();
      pizza.box();
      
      return pizza;
   }
}