Optional parameters on request class

Question

What is the proper way to handle optional parameters on a service request?

Lets say in this scenario i want to have also $title as optional parameter

<?php
namespace Lw\Application\Service\Wish;
class AddWishRequest
{
    private $userId;
    private $email;
    private $content;

    public function __construct($userId, $email, $content)
    {
        $this->userId = $userId;
        $this->email = $email;
        $this->content = $content;
    }

    public function userId()
    {
        return $this->userId;
    }

    public function email()
    {
        return $this->email;
    }

    public function content()
    {
        return $this->content;
    }
}

Example from here

Answer 1

Usually in DDD and following the rules of clean code also, if you have optional parameters, you have multiple constructors, two in this case:

• One for just the mandatory arguments.

• One for all the arguments including the optional but in this constructor it would be mandatory too.

If you wanna construct the object without the optional argument you call the first one. And if you wanna supply a non null optional argument you use the second one.

Usually you should use factory methods with meaningful names, and hide the constructors.

AddWishRequest.create ( userId, email, content)

AddWishRequest.createWithTitle ( userId, email, content, title )