gistfile1.txt

Step 1 : Create abstract and concrete classes

//abstract class Pizza
public abstract class Pizza {
     
    public abstract void bakePizza(); 
}

//CheesePizza subclass
public class CheesePizza extends Pizza {
   
    @Override
    public void bakePizza() {
        //TODO
        System.out.println("Bake Cheese Pizza");
    } 
}

//VeggiePizza subclass
public class VeggiePizza extends Pizza {
   
    @Override
    public void bakePizza() {
        //TODO
        System.out.println("Bake Veggie Pizza");
    } 
}


Step 2 : Create Pizza AbstractFactory interface or abstract class

public interface PizzaAbstractFactory {

	public Pizza orderPizza();
   
}

Step 3: Create Factory class for each subclass

public class CheesePizzaFactory implements PizzaAbstractFactory {
	@Override
	public  Pizza orderPizza() {
		return new CheesePizza();
	}
  
  public class VeggiePizzaFactory implements PizzaAbstractFactory {
	@Override
	public  Pizza orderPizza() {
		return new VeggiePizza();
	}
  
  Step 4: Create a consumer class that will provide the entry point for the client classes to create sub-classes.
  public class PizzaFactory {

	public static  getPizza(PizzaAbstractFactory factory){
		return factory.orderPizza();
	}
}

Step 5: Write a simple test method and see how to use the abstract factory to get the instance of sub-classes.

public class DesignPatternExample {

	public static void main(String[] args) {
		Pizza cheesePizza = PizzaFactory.getPizza(new CheesePizzaFactory());
		Pizza veggiePizza = PizzaFactory.getPizza(new VeggiePizzaFactory());
	
	}
}