Mastering PHP 7

Creating a custom exception handler

By extending the built-in Exception class, PHP lets us throw any object as if it were an exception. Let's take a look at the following example:

    <?php    class UsernameException extends Exception {}    class PasswordException extends Exception {}    $username = 'john';    $password = '';    try {      if (empty($username)) {        throw new UsernameException();      }      if (empty($password)) {        throw new PasswordException();      }      throw new Exception();    }     catch (UsernameException $e) {      echo 'Caught UsernameException.';    }     catch (PasswordException $e) {      echo 'Caught PasswordException.';    }     catch (Exception $e) {      echo 'Caught Exception.';    }     finally {      echo 'Finally.';    }

Here, we defined two custom exceptions, UsernameException and PasswordException ...