Re: [groovy-dev] Regd DGM

My Accounts class may be several things. It will mostly likely have
some notion of how to step through its accounts but I am not sure
there is much benefit in forcing it to implement java.util.Iterator.
Groovy lets me adopt interface oriented programming if I choose but
also has the hooks for duck typing too.

Paul.

Saager Mhatre wrote:
> wait, but wouldn't your Customer.accounts be some form of Collection? 
> GPath expressions could also be coercable to Collections. Then we're 
> golden without having to pollute Object.
> 
> On Mon, Jun 2, 2008 at 1:04 PM, Paul King <paulk@... 
> <mailto:paulk@...>> wrote:
> 
>     Saager Mhatre wrote:
> 
>         I know what Duck typing is, and don't particularly like it.
>         Besides, I don't think we should have duck typing over a Class
>         based OO platform; creates room for too much confusion.
> 
>         I just felt like it was polluting the interface of java.lang.Object.
> 
> 
>     The current solution while not perfect provides some nice convenience
>     once you become familiar with it. If in my Customer class I have a
>     reference to an Accounts class then I can say:
> 
>     customer.accounts.findAll{ a -> a.balance > 0 }
> 
>     rather than forcing Accounts to implement java.util.Iterator or
>     using the more cumbersome:
> 
>     customer.accounts.iterator().findAll{ a -> a.balance > 0 }
> 
>     For this simple case it might not appear to make much difference
>     but the subtle difference is the basis of what makes GPath work
>     as nicely as it does.
> 
>     Paul.
> 
> 
>         IMHO, if you're calling an internal iterator method (each, find,
>         any, all, ...) on a non-iterable, the system shoudl just give
>         you a sensible exception instead of defaulting to  returning the
>         object itself. The current approach seems to have the potential
>         to mask possible errors.
> 
>         On Sun, Jun 1, 2008 at 5:00 AM, Martin C. Martin
>         <martin@... <mailto:martin@...>
>         <mailto:martin@...
>         <mailto:martin@...>>> wrote:
> 
> 
> 
>                Saager Mhatre schrieb:
> 
>                    Then why not just add them into java.util.Iterator
>         and array
>                    variants? Why java.lang.Object? Isn't that a smell?
>         Aren't
>                    we polluting the interface of java.lang.Object?
> 
>                    I know that's a lotta questions, but it's late and my
>         head's
>                    spinning! :S
> 
> 
>            It's duck typing:
> 
>            http://en.wikipedia.org/wiki/Duck_typing
> 
>            Best,
>            Martin
> 
> 
>          
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> 
>         -- 
>         Saager Mhatre
> 
> 
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> 
> -- 
> Saager Mhatre

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