ES Code Discussion

Even in the card example the bare int approach breaks down rather quickly.

I'll replace "card" with "entity"

entity.getAs(Card.class).suit -> which is 3;

In your code are you going to do what with 3? What is "3" anyway. Is it hearts, clubs, or diamonds? Nope it's spades.

switch (entity.getAs(Card.class).suit)
{
   case 3:
       switch (entity.getAs(Card.class).rank)
       {
           case 0:
               <do something with ace of spades or is it? >
               break;
       }
       break;
}

or some horrendous if / else block comparing both suit / rank in each conditional.

If you want to then define static types; IE

public abstract class CardDef
{
   public static final int CLUBS = 0;
   public static final int DIAMONDS = 1;
   public static final int HEARTS = 2;
   public static final int SPADES = 3;

   public static final int ACE = 0;
   public static final int TWO = 1;
   ...
   public static final int KING = 12;
}

and replace the hard coded ints in the switch statement with the the above separate definitions you've now made it a little more legible, but still have the nested mess and the potential for error handling needs to be explicitly enforced all over the place as it would be a tragedy if at some point a cards suit was set to 3485891 and rank to 123895912; for whatever reason.

or does this make more sense:

switch (entity.getAs(FrenchDeckCard.class))
{
    case ACE_OF_SPADES:
         <do something obvious here>
         break;
}

one can also specifically get the rank / suit separately:

entity.getAs(FrenchDeckCard.class).suit == SPADES

how is this OOP?

public enum FrenchCardDeck implements ICOPExtensibleEnum
{
    public enum Suit { CLUBS, HEARTS, DIAMONDS, SPADES }
    public enum Rank { ACE, TWO, THREE, FOUR ... KING }

    ACE_OF_CLUBS(CLUBS, ACE),
    TWO_OF_CLUBS(CLUBS, TWO),
    ...
    KING_OF_SPADES(SPADES, KING);

    public final Suit suit;
    public final Rank rank;

    FrenchCardDeck(Suit suit, Rank rank)
    {
        this.suit = suit;
        this.rank = rank;
    }
}