Abstract Factory Pattern

All factory patterns encapsulate object creation. The Factory Method Pattern encapsulates object creation by letting subclasses decide what objects to create.

The Factory Method Pattern defines an interface for creating an object, but lets subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses.

The Abstract Factory Pattern provides an interface for creating families of related or dependent objects without specifying their concrete classes.

Abstractions

public interface PizzaIngredientFactory {
 
	public Dough createDough();
	public Sauce createSauce();
	public Cheese createCheese();
	public Veggies[] createVeggies();
	public Pepperoni createPepperoni();
	public Clams createClam();
 
}

public interface Cheese {
	public String toString();
}

public interface Dough {
	public String toString();
}

public abstract class Pizza {
	String name;

	Dough dough;
	Sauce sauce;
	Veggies veggies[];
	Cheese cheese;
	Pepperoni pepperoni;
	Clams clam;

	abstract void prepare();

	void bake() {
		System.out.println("Bake for 25 minutes at 350");
	}

	void cut() {
		System.out.println("Cutting the pizza into diagonal slices");
	}

	void box() {
		System.out.println("Place pizza in official PizzaStore box");
	}

	void setName(String name) {
		this.name = name;
	}

	String getName() {
		return name;
	}

	public String toString() {
		StringBuffer result = new StringBuffer();
		result.append("---- " + name + " ----\n");
		if (dough != null) {
			result.append(dough);
			result.append("\n");
		}
		if (sauce != null) {
			result.append(sauce);
			result.append("\n");
		}
		if (cheese != null) {
			result.append(cheese);
			result.append("\n");
		}
		if (veggies != null) {
			for (int i = 0; i < veggies.length; i++) {
				result.append(veggies[i]);
				if (i < veggies.length-1) {
					result.append(", ");
				}
			}
			result.append("\n");
		}
		if (clam != null) {
			result.append(clam);
			result.append("\n");
		}
		if (pepperoni != null) {
			result.append(pepperoni);
			result.append("\n");
		}
		return result.toString();
	}
}

public abstract class PizzaStore {
 
	protected abstract Pizza createPizza(String item);
 
	public Pizza orderPizza(String type) {
		Pizza pizza = createPizza(type);
		System.out.println("--- Making a " + pizza.getName() + " ---");
		pizza.prepare();
		pizza.bake();
		pizza.cut();
		pizza.box();
		return pizza;
	}
}

Implementations

public class ParmesanCheese implements Cheese {

	public String toString() {
		return "Shredded Parmesan";
	}
}

public class CheesePizza extends Pizza {
	PizzaIngredientFactory ingredientFactory;
 
	public CheesePizza(PizzaIngredientFactory ingredientFactory) {
		this.ingredientFactory = ingredientFactory;
	}
 
	void prepare() {
		System.out.println("Preparing " + name);
		dough = ingredientFactory.createDough();
		sauce = ingredientFactory.createSauce();
		cheese = ingredientFactory.createCheese();
	}
}

public class ChicagoPizzaIngredientFactory 
	implements PizzaIngredientFactory 
{

	public Dough createDough() {
		return new ThickCrustDough();
	}

	public Sauce createSauce() {
		return new PlumTomatoSauce();
	}

	public Cheese createCheese() {
		return new MozzarellaCheese();
	}

	public Veggies[] createVeggies() {
		Veggies veggies[] = { new BlackOlives(), 
		                      new Spinach(), 
		                      new Eggplant() };
		return veggies;
	}

	public Pepperoni createPepperoni() {
		return new SlicedPepperoni();
	}

	public Clams createClam() {
		return new FrozenClams();
	}
}

Runner

public class PizzaTestDrive {
 
	public static void main(String[] args) {
		PizzaStore nyStore = new NYPizzaStore();
		PizzaStore chicagoStore = new ChicagoPizzaStore();
 
		Pizza pizza = nyStore.orderPizza("cheese");
		System.out.println("Ethan ordered a " + pizza + "\n");
 
		pizza = chicagoStore.orderPizza("cheese");
		System.out.println("Joel ordered a " + pizza + "\n");

		pizza = nyStore.orderPizza("clam");
		System.out.println("Ethan ordered a " + pizza + "\n");
 
		pizza = chicagoStore.orderPizza("clam");
		System.out.println("Joel ordered a " + pizza + "\n");

		pizza = nyStore.orderPizza("pepperoni");
		System.out.println("Ethan ordered a " + pizza + "\n");
 
		pizza = chicagoStore.orderPizza("pepperoni");
		System.out.println("Joel ordered a " + pizza + "\n");

		pizza = nyStore.orderPizza("veggie");
		System.out.println("Ethan ordered a " + pizza + "\n");
 
		pizza = chicagoStore.orderPizza("veggie");
		System.out.println("Joel ordered a " + pizza + "\n");
	}
}