Re: Programming to an Interface

Laurent Bossavit wrote:
Bernard,


Could you please transform this example to "programming to an
interface", still in Ruby to allow us to compare?


(In the original, btw, I meant "account.getId" rather than "amount.getId"...) In Ruby, perhaps we could come to:

def debitAccount amount
transaction = makeTransaction()
transaction.execute(this) {balance -= amount}
end

That is, the mechanics of persisting changes to an object and wrapping the business logic in a transaction would be hidden at the next level down. You don't care how persistence or transactions are implemented, only that you can rely on both.

Laurent

You'd probably want:

def debit_account amount
transaction do
balance -= amount
end
end

I fail to see how this has anything to do with programming to an interface rather than implementation though.

Joe
.

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