The following code extends Exception to create custom exception.
<?php
use Exception;
class InvalidIdException extends Exception {
public function __construct($message = null) {
$message = $message ?: 'Invalid id provided.';
parent::__construct($message);
}
}
...
The InvalidIdException class extends from the class Exception.
The constructor of the class takes an optional argument, $message.
The ?: operator is a shorter version of a conditional.
parent::__construct will invoke the parent's constructor.
We can use this new exception.
throw new InvalidIdException('Id cannot be a negative number.');