[FLOW3-general] Relation to value object and general question regarding value objects

[Kevin Ulrich Moschallski]

Hi again,

i just wanted to ask what the added paragraph in the documentation means:

"Declares a class as a Value Object, allowing the persistence framework 
to reuse an existing object if one exists. Doctrine 2 does not (yet) 
support value objects, thus we handle this like an entity for the time 
being."

AFAIK this was added by Karsten, as far as i read on the core-v5 list.

Does this mean that valueobjects are handled like entities or does that 
mean that the @entity shouldn't be uses at the moment?

For my second question i asked i now bought the DDD book from Eric 
Evans, hopefully this will answer my question :), but maybe somebody 
gives me a jump start.

Greetings,
Kevin

On 2011-08-23 20:48:53 +0000, Kevin Ulrich Moschallski said:

> Hi list,
> 
> i just created a small FLOW3 project. In this project i have an object 
> called GeoLocation which has the properties longitude and latitude. I 
> wanted this object to be an value object so i added the @valueobject 
> notation and wrote the constructor and the getters:
> 
> /**
>  * A Geo location
>  *
>  * @scope prototype
>  * @valueobject
>  */
> class GeoLocation {
>     /**
> 	 * @var float
> 	 */
> 	protected $longitude;
> 
>     /**
> 	 * @var float
> 	 */
> 	protected $latitude;
> 
> 	/**
> 	 * Constructs this location
> 	 *
> 	 */
> 	public function __construct($longitude, $latitude) {
> 		if (!is_float($longitude)) {
> 			throw new \InvalidArgumentException('A float value for longitude 
> must be passed to this constructor.', 1314040680);
> 		}
> 		$this->longitude = $longitude;
>         if (!is_float($latitude)) {
> 			throw new \InvalidArgumentException('A float value for latitude must 
> be passed to this constructor.', 1314040681);
> 		}
> 		$this->latitude = $latitude;
> 	}
> 
> 	/**
> 	 * Returns longitude
> 	 *
> 	 * @return float
> 	 */
> 	public function getLongitude() {
> 		return $this->longitude;
> 	}
> 
>     /**
> 	 * Returns latitude
> 	 *
> 	 * @return float
> 	 */
> 	public function getLatitude() {
> 		return $this->latitude;
> 	}
> 
> }
> 
> ----
> 
> In a second object (address) i added a geolocation property:
> 
> /**
> 	 * The geoLocation
> 	 *
> 	 * @var \ThreeDigit\PunchMe\Domain\Model\GeoLocation
>      * @ManyToOne
> 	 */
> 	protected $geoLocation;
> 
> When i run typo3.flow3:doctrine:create i get an error about the missing 
> id property for the relation.
> 
> Now i read on the doctrine documentation, that value objects are only 
> supported if they're an instance of DateTime.
> 
> So my two questions are:
> 
> - Is there a way to get a relation to an value object in FLOW3, i read 
> something about serialize the object?
> - And more general, is the decission to setup my GeoLocation object as 
> value object i good one, or should it be a entity?
> 
> I'm looking forward to hear your replies to learn more about value objects.
> 
> Regards,
> Kevin