PHP how to create a final class

PHP provides you with the final keyword that you can use as a modifier for classes and functions.

When you add the final keyword to a class, that class can’t be extended.

Here’s an example of creating a final class:

<?php

final class Car {
    function start(){
        print "Start the engine";
    }
}

PHP will throw an error when you try to extend a final class as shown below:

class Tesla extends Car {}
// Fatal error: 
// Class Tesla cannot extend final class Car

The final keyword is useful to restrict a class, removing the possibility of extending that class.

You can also put the final keyword in front of class functions to disable child classes from overriding that function:

<?php

class Car {
  final function start(){
      print "Start the engine";
  }
}

class Tesla extends Car {
  // 👇 Cannot override final method Car::start()
  function start(){
    print "Tesla starting...";
  }
}

Now you’ve learned how to create a final class in PHP.