Using named constructors for data transfer objects

NamedDTO.php

<?php

namespace Acme;

class DataTransfer
{
    public static function forUser(
        $user_id
    ) {
        return new static($user_id);
    }
    
    public static function forCompany(
        $company_id
    ) {
        return new static(null, $company_id);
    }
    
    private $user_id;
    private $company_id;
    
    public function userId()
    {
        return $this->user_id;
    }
    
    public function companyId()
    {
        return $this->company_id;
    }
    
    private function __construct(
        $user_id = null,
        $company_id = null
    ) {
        if ($user_id) {
            $this->user_id = $user_id;
        }
        
        if ($company_id) {
            $this->company_id = $company_id;
        }
    }
}

What I love about this is that it hides changes to the constructor and makes it really easy use:

$dto = DataTransfer::forUser($_POST['user_id']);
// or
$dto = DataTransfer::forCompany($_POST['company_id']);

Many named constructors can be added the class to account for different variations in the data, all without worrying about existing code blowing up because the constructor order changed!

References: Named Constructors in PHP