On 20 Oct 2008, at 20:24, Christoph Boget wrote:
public function __construct()
A singleton would usually have a private constructor to prevent
non-singleton instances.
The problem being if the class in question derives from another class
that has a public constructor... If you are in that particular
situation (which I am), you're basically SOL and the statement above
has no bearing.
Correct, but you're then breaking one of the rules of the singleton
pattern. If you're stuck with that then you'll need to enforce the
singleton aspect in non-technical ways (policy, regular beatings, etc).
Singletons are not rocket science, but as with all patterns you
really need
to understand the theory before trying to implement and use it.
Agreed. But apparently implementing them in PHP leaves things to be
desired.
Not really, not if you do it correctly. As far as I can tell, apart
from getting it completely wrong (it would have been wrong in all
languages I can think of) the only issue you've come across is not
being able to extend a class with a public constructor. If that's the
only issue you can find then I don't see much to be desired.
I don't know the exact reason for this limitation but I'm sure there's
a good one. The core PHP devs don't make a habit of enforcing
arbitrary limitations like that. If you think it's worth fixing feel
free to report it as a bug at http://bugs.php.net/ and you'll probably
get told the reason it's like that.
-Stut
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http://stut.net/
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