>> 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.
>> {
>> echo 'singleTon::__construct()<br>';
>> if( !is_null( singleTon::$thisObj ))
>> {
>> echo '$thisObj already set. returning it...<br>';
>> return singleTon::$thisObj;
>> }
>> singleTon::$thisObj = $this;
> 1) You don't return it unless it already exists, not that it matters because
> this is the constructor and you can't return anything from that.
> 2) The constructor has no involvement in management of the singleton
> instance so this is just all wrong.
I did this mainly to see if it would have any effect.
>> public static function singleton()
>> {
> That method has the same name as the class. I'm not sure what effect this
> will have but it's certainly to be discouraged.
It has no effect. And yes, that is true in general, but this is just
a test foobar class.
> Here's the simplest example I can think of (untested, typed straight into my
> mail client)...
This won't work if derived from a class with a public constructor.
That's why my test class' constructor was defined public.
> 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.
thnx,
Christoph
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