Doctrine 2 Value Objects

Question

I have been implementing value objects as custom DBAL types in Doctrine 2 and it\'s been working OK. However I have been wondering if this is the best way. I\'ve thought about u

Answer 1

IMHO, both approaches are equally valuable, while waiting for native support for value objects.

I personally favor the second approach (instantiating them through accessors when requested) for two reasons:

• As you mentioned, it offers better performance as the conversion is only done when needed;
• It decouples your application from Doctrine dependency: you're writing less code that is Doctrine-specific.

An example of this approach:

class User
{
    protected $street;
    protected $city;
    protected $country;

    public function setAddress(Address $address)
    {
        $this->street  = $address->getStreet();
        $this->city    = $address->getCity();
        $this->country = $address->getCountry();
    }

    public function getAddress()
    {
        return new Address(
            $this->street,
            $this->city,
            $this->country
        );
    }
}

This code will be fairly easy to refactor when Doctrine will offer native VO support.

About custom mapping types, I do use them as well, for single-field VO (Decimal, Point, Polygon, ...) but would tend to reserve them for general-purpose, reusable types that can be used across multiple projects, not for project-specific single-field VO where I would favor the approach above.