DDD构建一个包含集合属性的值对象

Question

i have a simple question when building a value object that has a collection of value objects inside it with a specific type how do you construct the object ?

to take an example lets say you have a picture that take multiple dimensions

Option 1 :

Class Picture implements valueObject{

    public function __construct(array $dimensions){
        foreach($dimensions as $dimension){
                // check if instance of `dimension` value object
        }
    }
}

Option 2 :

Class Picture implements valueObject{

    public function __construct(DimensionCollection $dimensions){

    }
}

Class DimensionCollection implements Traversable{

    public function add(Dimension $dimension){
        // add to array 
    }
}

Option two off-course seems more logical but is there another pattern that is better taken this from DDD preceptive ?

Answer 1

If your Picture VO holds a collection..then I'd name it Pictures or PictureCollection because it will be made of of other Picture objects. (as you did with dimensions).

Although this is a review matter valueObject interface should be named "ValueObjetct" with a capital "V".

I think your domain needs a bit of restructuring. If a Picture has Dimensions than Dimension"s" should be a group made of Dimension VOs.