Note: I'm using PHP, but I think this question would be considered language agnostic. I'm also implementing "lite DDD", but I don't think that restricts the question any either.
I have a class (entity) with a lot of properties that can be set (I also have a lot of behavior on the entity, so it's not an anemic domain model).
For example, I have many string properties that look like the following:
public function setFirstName($firstName)
{
// Removes all non-printable characters and extra spaces.
// Also converts all "look-a-like" quotes to the standard quote character.
$firstName = Helper::cleanName($firstName);
if(empty($firstName)){
throw new \Exception("first name is required");
}
$this->firstName = $firstName;
}
Adhereing to DRY, I see benefit in creating a "clean name" value object. But this will turn almost all of my string properties into these value objects. I also have other properties that are dates that I would turn into Carbon date value objects. In the end, it seems almost every property (that will be persisted) has become a value object. I'm concerned if I'm over-using this approach, or if there are any memory-related problems that could arrise (especially in larger collections of these entities).
How does one go about determining if a class is over-using value objects? Ie. is there a minimum standard to the amount of logic to be encapsulated to be a value object? Am I blowing up memory by making almost every property (that will be persisted) a value object? Has anyone encountered issues with a class with perhaps 30+ value objects?
