Hi Ashley,
> -----Original Message-----
> From: Ashley Sheridan [mailto:a...@ashleysheridan.co.uk]
> Sent: Thursday, April 15, 2010 6:38 AM
> To: PHP General List
> Subject: [PHP] class attributes and __construct
>
> I think this is probably going to end up as one of those coders'
> preference type of things, but I was wondering what was considered the
> general best approach.
>
> When creating a class, you can define default values for the object in
> the class itself, and within the __construct function. Now, while I see
> the advantage to using __construct to set properties that might depend
> on a variable, what would be the best approach for any values that
> might
> likely remain at a default value and only ever change in a few rare
> circumstances?
>
> For example:
>
> class Person
> {
> public $right_handed = true;
I recommend setting it to private or protected instead of public to protect the
integrity of the app. And add a get method/function to obtain the value.
> function __construct($name, $height)
> {
> $this->name = $name;
> $this-height = $height;
> }
>
> function set_hand($side)
> {
> if($side == 'left'
> {
> $this->right_handed = false;
> }
> else
> {
> $this->right_handed = true;
> }
> }
>
> }
>
> Now, this is a simple example, but a value like $right_handed should
> only ever change if it's not the typical. As most people are
> right-handed it would make sense to set it to true and allow it to be
> changed to false as necessary. What I'm wonder is, where is the best
> place to set it to true, in the list of class properties at the top, or
> in the __construct() function?
>
> I know I could move it to __construct and give it a default value in
> the
> arguments list, but that brings it's own problems. What if the argument
> list grows too big, and which attribute would be deemed more important
> than another that you might want to override it without specifying
> every
> other? Is there a rule of thumb as to what belongs in __construct and
> what does not?
>
> Thanks,
> Ash
> http://www.ashleysheridan.co.uk
>
As for setting the default value in the construct, I recommend not to because
should PHP support overloading later, you can then have another method/function
to change its non-default value along with the initial parameters for the
class. I use the constructor to set initial parameters for the class or
initialize any class specific settings such as connection for DBAL.
Regards,
Tommy
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