Posted by Rik on 06/23/07 00:25

On Sat, 23 Jun 2007 00:18:56 +0200, <grossespinne@gmail.com> wrote:

> Hi everybody!
> I have been thinking over the following problem:
> there are three classes: PageBase, which is the base class, PageA and
> PageB which are the subclasses of PageBase.
> In the index.php file I have a variable which I like to hold either an=

> instance of PageA or PageB depending on the query string that is
> passed to index.php (e.g: if I get the query index.php?content=3Da, I
> need an instance of PageA, but if I get the query: index.php?
> content=3Db, an instance of PageB is needed)
>
> Until now I found two solutions, but I am not satisfied with either of=

> them:
> - use a switch structure
> - or use eval:
>
> $pageType =3D isset($_GET["page"]) ? $_GET["page"] : "PageBase";
> $thePage =3D eval("return new $pageType();");

First of all, what is wrong with dropping the eval, and just creating =

objects on the fly? So:

$pageType =3D (isset($_GET['page'] && =

class_exists('Page'.strtoupper($_GET['page'][1]) ? 'Page'.$_GET['page'][=
1] =

: 'PageBase';
$thePage =3D new $pageType();

> My question is whether a more object-oriented way exists to solve the
> problem.

Indeed, like others said, check Factory patterns.
-- =

Rik Wasmus

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