The best way to implement Factory without if, switch

Question

I was looking through many approaches to implement a Factory pattern in Java and still couldn\'t find a perfect one which doesn\'t suffer from both if/switch plus doesn\'t u

Answer 1

Try something like this:

class MyFactory {
    private static final Map> factoryMap =
        Collections.unmodifiableMap(new HashMap() {
            put("Meow", Cat.BASE_INSTANCE);
            put("Woof", Dog.BASE_INSTANCE);
    });

    public Animal createAnimal(String action) {
        return factoryMap.get(action).instance();
    }
}

interface Animal {
    public SELF instance();
}

class Cat implements Animal {
    public static final Cat BASE_INSTANCE = new Cat();
    public Cat() {}
    public Cat instance(){
        return new Cat();
    }
}
// And a similar Dog class

This does not use reflection, if, or switch, at all.