On Tue, Jun 30, 2009 at 10:44 AM, Luke<[email protected]> wrote:
>
>
> 2009/6/30 Eddie Drapkin <[email protected]>
>>
>> It should be passed into the constructor as a parameter. If you're
>> using OOP properly, there's no reason to use $GLOBALS, ever. Any
>> variable in the $GLOBALS array exists twice in memory, so just keep
>> that in mind, if you plan to use it.
>>
>> On Tue, Jun 30, 2009 at 8:43 AM, Peter Ford<[email protected]> wrote:
>> > Luke wrote:
>> >> Hello again guys,
>> >>
>> >> I was wondering the best way to tackle the following problem:
>> >>
>> >> I've got a class, containing a property which is another object. So
>> >> from
>> >> outside I should be able to do
>> >> $firstobject->propertycontainingobject->methodinsidethatobject();
>> >>
>> >> The $firstobject variable is in the global namespace (having been made
>> >> with
>> >> $firstobject = new FirstObject;), and I'm having a problem that I'm
>> >> sure
>> >> many people have when accessing it inside another class, so:
>> >>
>> >> class otherObject
>> >> {
>> >> static function messwithotherthings ()
>> >> {
>> >> $firstobject->propertycontainingobject->methodinsidethatobject();
>> >> }
>> >> }
>> >>
>> >> But $firstobject is blank, which makes sense because in there it is
>> >> pointing
>> >> to the local variable within the method.
>> >>
>> >> To solve this, I could add 'global $firstobject' inside every method,
>> >> but
>> >> this is very redundant and boring. I've tried a couple of things like
>> >> adding:
>> >>
>> >> private $firstobject = $GLOBALS['firstobject'];
>> >>
>> >> But apparently that's bad syntax. I was just wondering the best way to
>> >> get
>> >> around this?
>> >>
>> >> Thanks a lot for your help,
>> >>
>> >
>> >
>> > Set the value of $firstobject in the constructor of otherObject (that's
>> > what
>> > constructors are for!):
>> >
>> > eg.
>> >
>> > class otherObject
>> > {
>> > private $firstobject;
>> >
>> > function __construct()
>> > {
>> > $this->firstobject = $GLOBALS['firstobject'];
>> > }
>> >
>> > static function messwithotherthings ()
>> > {
>> >
>> > $this->firstobject->propertycontainingobject->methodinsidethatobject();
>> > }
>> > }
>> >
>> >
>> > --
>> > Peter Ford phone: 01580 893333
>> > Developer fax: 01580 893399
>> > Justcroft International Ltd., Staplehurst, Kent
>> >
>> > --
>> > PHP General Mailing List (http://www.php.net/)
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>> >
>> >
>>
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>>
>
> Thanks for the replies :)
>
> Surely if I pass it as a parameter to the __construct then I would have to
> make an instance of the otherObject, notice that messwithotherthings is
> static?
>
> Also, if I'm not using OOP properly, Eddie, how would I use it properly to
> prevent this situation?
>
> Thanks,
>
> --
> Luke Slater
> :O)
>
>
Well all you'd really need to do is something like this (for an instance class):
class ExampleClassYay {
private $instance;
public function __construct(someOtherClass $instance) {
$this->instance = $instance;
}
public function foo() {
var_dumP($this->instance);
}
}
So, all you'd have to do is something like:
$foo = new someOtherClass();
$example = new ExampleClassYay($foo);
$example->foo();
Whereas, for a static class, you can use a static property accessed
via self::$property instead of $this->property, like so:
Well all you'd really need to do is something like this:
class StaticExampleClassYay {
private static $instance;
static public function setInstance(someOtherClass $instance) {
self::$instance = $instance;
}
static public function foo() {
var_dump(self::$instance);
}
}
In which case, it'd be something like
$foo = new someOtherClass();
StaticExampleClassYay::setInstance($foo);
StaticExampleClassYay::foo();
What I meant, and I probably sounded a bit rougher than I absolutely
had to, was that it's pretty universally lazy and/or bad design to use
global variables inside a class, because classes have member
properties. From a purely philosophical standpoint, classes are
supposed to be entirely self-contained and any data that a method
needs to process is supposed to be passed as a parameter, or exist
inside the class as a property. It helps to think of classes like
cars on a highway; if you want it to go faster, you give it some gas
(pass a method a parameter), but if you want to turn on some music
while driving, the CDs should already exist in the car (accessing a
member property) even though they might have been added earlier (via a
different method with other parameters). That's probably not the
greatest metaphor, but I hope you see what I'm saying.
--Eddie
PS. sorry for sounding rough :)
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