Factory Method VS Factory Object [duplicate]

Question

As I understand Factory Method is Simple Factory and Factory Object is Abstract Factory? And:

-Factory Method (Simple Factory):

public class SimplePizzaFactory {
    public static final int CHEESE = 1;
    public static final int PEPPERONI = 2;
    public static final int VEGGIE = 3;

    public static Pizza createPizza(int type) {
        Pizza pizza = null;

        if (type == CHEESE) {
            pizza = new CheesePizza();
        } else if (type == PEPPERONI ) {
            pizza = new PepperoniPizza();
        } else if (type == VEGGIE ) {
            pizza = new VeggiePizza();
        }

        return pizza;
    }
}

Factory Object(Abstract Factory):

?

Am I right?

How much are there realizations of Factory patterns and what is their difference?

Yoko

Just another thing, unless you're using some ancient version of Java, please use enum instead of ints to enumerate possible types of pizza. – Rossi

+1, I found this ancient example.(Java that time had not enums yet.) – Yoko

Answer 1

No. A factory-method is a factory that does not require any state. A factory class is a class itself - it has state, and methods that alter that state. In the end you call the .create() method, and it uses its current state to create a new object of a different type.

Abstract factory is a different thing - there you have multiple factory implementations of the same abstract concept. The wikipedia example is about e GUIFactory - this is an abstract factory, which has two implementations: WinFactory and OSXFactory. The client code does not know which implementation it is using - it just knows the factory creates Button instances. Which make it possible to write the same code regardless of the OS.

Jaal

So there are 3 main types: - Factory - Abstract Factory - Factory method ? – Yoko

yes, that's correct. The factory and factory method don't differ that much though. – Jaal

Your answer is clear. I understand what is difference between Factory and factory method, but which is better to use? and why? – Weapon

that's the point - there is no silver bullet :) Factory method is likely to be applicable in more situations, I think – Jaal