What are the Benefits and Usage of PHP\'s `::class` Notation?
Dec 08, 2024 pm 03:06 PM
Understanding PHP's ::class Notation
The ::class notation in PHP is a powerful feature that allows you to obtain the fully qualified name of a class, including its namespace. Introduced in PHP 5.5, this notation provides significant advantages in code readability, refactoring, and late static binding.
Benefits of Using ::class
There are several advantages to using the ::class notation:
- Enhanced Class Reference: You no longer need to store class names as strings. IDEs can now automatically extract and use these class names for refactoring purposes.
- Namespace Resolution: The use keyword can be combined with ::class to resolve classes without the need to specify the full class name. This simplifies code and improves readability.
- Late Static Binding: In parent classes, you can use static::class to determine the name of the derived class, providing more flexibility in class inheritance.
Syntax and Usage
The syntax of ::class is straightforward:
SomeClass::class
This notation will return the fully qualified name of SomeClass, including its namespace prefix.
Examples
Consider the following example:
protected $commands = [
\App\Console\Commands\Inspire::class,
];
Using ::class eliminates the need for hard-coded class names, making it easier to maintain and update the array of commands.
Late Static Binding Example
The following example demonstrates late static binding using the ::class notation:
class A {
public function getClassName(){
return __CLASS__;
}
public function getRealClassName() {
return static::class;
}
}
class B extends A {}
$a = new A;
$b = new B;
echo $a->getClassName(); // A
echo $a->getRealClassName(); // A
echo $b->getClassName(); // A
echo $b->getRealClassName(); // B
As you can see, the getRealClassName() method in the parent class A uses static::class to obtain the name of the derived class B, demonstrating the benefits of late static binding.
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