Access Static properties using PHP object

Question

This is with reference to Get a static property of an instance, I am a newbie and have the following code :

class Foo
{
   public static $my_static = 1;
}

class Bar extends Foo
{

}

$foo = new Foo();
$boo = new Bar();

echo Foo::$my_static;  // ok
echo Bar::$my_static;  // ok
echo $foo::$my_static; // ok
echo $boo::$my_static; // ok

Static variables/properties are accessed only as ClassName::static_property as in C++, but it is not the case in PHP... but PHP books mostly mention the className::static_property pattern, not the object::static_property construct. Need more light on this..

also, from inside a class you may use `self::$my_static` or `static::$my_static` (see [late static bindings](http://php.net/manual/en/language.oop5.late-static-bindings.php) for the `static::` usage (since PHP 5.3) — Carlos Campderrós, Jun 14 '13 at 11:55
check this link it may help... http://php.net/manual/en/language.oop5.static.php — Muhammad Saqlain Arif, Jun 14 '13 at 12:03

score 25 · Accepted Answer · answered Jun 14 '13 at 11:56

Static properties may be accessed on various ways.

Class::$aStaticProp; //by class name

$classname::$aStaticProp; // As of PHP 5.3.0 by object instance

Static properties cannot be accessed through the object using the arrow operator ->.

As of PHP 5.3.0, it's possible to reference the class using a variable. The variable's value can not be a keyword (e.g. self, parent and static).

More you can read in manual

score 12 · Answer 2 · answered Jun 14 '13 at 11:55

12

$instance::$staticProperty is simply a convenience shorthand for Class::$staticProperty. Since you already have an instance of a class and the syntax is unambiguous, PHP saves you from writing a potentially long class name. There's no functional difference.

answered Jun 14 '13 at 11:55

deceze

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I do have a followup annoyance, since I'm a bit in disbelief that this works: `$instance::$staticProperty` does not make sense to me. The static property belongs to the class, not the object. Why does the interpreter allow this to slide for 'convenience'? – BLaZuRE Jun 14 '13 at 12:01
Sometimes when you hold name of classes in strings and you're doing dynamic operations of them it's very useful. – Robert Jun 14 '13 at 12:03
@Robert I guess it should make sense to me because PHP isn't the strictest of languages, but you could simply use `get_class()` to get the object's class name. – BLaZuRE Jun 14 '13 at 12:08
1

@BLaZuRE `$foo::$bar` → *"Get the static property `$bar` of the class `$foo` is an instance of."* It's just syntactic sugar and seems mightily convenient to me. :-3 – deceze Jun 14 '13 at 12:11

score 3 · Answer 3 · answered Aug 23 '15 at 23:55

3

within the class you have to use like self::$staticPropery if the function accessing to the variable is also static.

answered Aug 23 '15 at 23:55

Alp Altunel

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Access Static properties using PHP object

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