Java Super and Sub Classes

[JGC84]

Ok so i've got a game, with class Player, and a few extensions of Player

i've greatly over simplified my code for ease of my typing.

class Player
    public PlayerStuff;
class SmartPlayer extends Player
    public SmartStuff;
class HumanPlayer extends Player;
    Public HumanStuff;

then in my game class i'm trying to define an array of players that is a mix of players, smartplayers and humanplayers.

Player[NUM_OF_PLAYERS] PlayersInGame;

PlayersInGame[1] =  new Player;
PlayersInGame[2] = new SmartPlayer;

and the problem arises that i cant access the methods in SmartPlayer even if instances of the array is pointed at a SmartPlayer... any ideas?

[xclite]

The reason for that is that the compiler has no way of guaranteeing that a reference in an array of Players has the methods within the SmartPlayer class. Since you could just as easily store a HumanPlayer there that does not have the method, the compiler forces you to make such a guarantee.

There are two ways around this.
1) I call this the wrong way, but sometimes you can't avoid it. You could force the instance to be a smart player with a cast, so something like:

((SmartPlayer)PlayersInGame).methodInSmartPlayer();

To be even safer, you could do an instanceof check, so that you never get a ClassCastException if you accidentally do that with the wrong class.

2) Only call methods that are guaranteed to be common among Player - if the method you are trying to call can be made abstract in Player and then implemented in both, then by all means take this route.

[JGC84]

can you typecast as things other then default types?

[xclite]

Yes indeed - and that TypeCast will actually work, provided what you are casting actually was instantiated as a SmartPlayer. If you tried the cast on a HumanPlayer, it would throw an exception during execution.

[JGC84]

awesome, thanks a bunch.

[xclite]

No problem.