factory methods.

[Aman]

why should factory methods be virtual in C++ ?
what would be the impact if they were not ?


--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

[Gianni Mariani]

Re: factory methods.

Aman wrote:[color=blue]
> why should factory methods be virtual in C++ ?
> what would be the impact if they were not ?[/color]

Why do you think you need a factory ?

Factories are usually used when you want to separate the implementation
from the interface.

Can you fill in the dots from there ?

[jeffc]

Re: factory methods.


"Aman " <aman@techie.co m> wrote in message
news:881dcb270e 2dc67e03b01625e 41cacd8.26421@m ygate.mailgate. org...[color=blue]
> why should factory methods be virtual in C++ ?[/color]

So the correct subclass of object is created.
[color=blue]
> what would be the impact if they were not ?[/color]

The correct subclass of object might not be created.

[Chris Theis]

Re: factory methods.


"Aman " <aman@techie.co m> wrote in message
news:881dcb270e 2dc67e03b01625e 41cacd8.26421@m ygate.mailgate. org...[color=blue]
> why should factory methods be virtual in C++ ?[/color]

Because a factory should be able to create different types of objects.
Probably you should think about the reason of using a factory once again.
[color=blue]
> what would be the impact if they were not ?
>[/color]
You'd have some more worries in your life....

Chris

[jeffc]

Re: factory methods.


"Chris Theis" <Christian.Thei s@nospam.cern.c h> wrote in message
news:bjqd9q$jh6 $1@sunnews.cern .ch...[color=blue]
>
> "Aman " <aman@techie.co m> wrote in message
> news:881dcb270e 2dc67e03b01625e 41cacd8.26421@m ygate.mailgate. org...[color=green]
> > why should factory methods be virtual in C++ ?[/color]
>
> Because a factory should be able to create different types of objects.
> Probably you should think about the reason of using a factory once again.
>[color=green]
> > what would be the impact if they were not ?
> >[/color]
> You'd have some more worries in your life....[/color]

I'm starting to think this was a homework question, verbatim.

[Jason Spashett]

Re: factory methods.

"Gianni Mariani" <gi2nospam@mari ani.ws> wrote in message
news:bjq683$oig @dispatch.conce ntric.net...[color=blue]
> Aman wrote:[color=green]
> > why should factory methods be virtual in C++ ?
> > what would be the impact if they were not ?[/color]
>
> Why do you think you need a factory ?
>
> Factories are usually used when you want to separate the implementation
> from the interface.
>
> Can you fill in the dots from there ?
>[/color]
No, what about static factory methods? They can't be virtual.

[Aman Angrish]

Re: factory methods.

heh heh,
no it's not a homework question !! (i'm lucky i don't get homework ).
just read this statement in Gamma (design patterns ) ,wanted to know
why.
Thanks for your inputs.
regards,
Aman.



"jeffc" <nobody@nowhere .com> wrote in message
news:3f60cb82_4 @news1.prserv.n et
[color=blue]
>
> "Chris Theis" <Christian.Thei s@nospam.cern.c h> wrote in message
> news:bjqd9q$jh6 $1@sunnews.cern .ch...[color=green]
> >
> > "Aman " <aman@techie.co m> wrote in message
> > news:881dcb270e 2dc67e03b01625e 41cacd8.26421@m ygate.mailgate. org...[color=darkred]
> > > why should factory methods be virtual in C++ ?[/color]
> >
> > Because a factory should be able to create different types of objects.
> > Probably you should think about the reason of using a factory once again.
> >[color=darkred]
> > > what would be the impact if they were not ?
> > >[/color]
> > You'd have some more worries in your life....[/color]
>
> I'm starting to think this was a homework question, verbatim.[/color]




--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

[Gianni Mariani]

Re: factory methods.

Jason Spashett wrote:[color=blue]
> "Gianni Mariani" <gi2nospam@mari ani.ws> wrote in message[/color]
....[color=blue][color=green]
>>
>>Can you fill in the dots from there ?
>>[/color]
>
> No, what about static factory methods? They can't be virtual.[/color]

What part of the fill-in-the-dots are you missing ?