What are the Benefits and Usage of PHP\'s `::class` Notation?

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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