Intent.Modelers.Domain.ValueObjects

A Value Object is a domain concept defined entirely by its values rather than by an identity — for example an Address or a Money amount. Two Value Objects with the same values are interchangeable.

The Intent.Modelers.Domain.ValueObjects module adds the Value Object element to the Domain Designer. How a Value Object is realized in code depends on the other modules installed, for example Intent.ValueObjects and your persistence module.

Modeling a Value Object

Right-click a Domain package, folder or diagram and select New Value Object (ctrl + shift + v), then add its values with Add Attribute (ctrl + shift + a).

A Value Object can be used as the type of:

• an Attribute
• an Operation's return type
• a Parameter, including Service Operation parameters and return types

Associations

An entity can be associated to a Value Object, and a Value Object can be associated to another Value Object.

To start an association from a Value Object, right-click it and select New Association (ctrl + shift + c), then choose One to One, One to Zero-or-One or One to Many. Selecting New Association itself creates a One to One association.

Only composite relationships are offered. When the target of an association is a Value Object, the source end is always set to exactly one (not a collection and not nullable): the Value Object is owned by the element that points to it.

A Value Object can't be associated to an entity. Value Objects are immutable values and shouldn't refer back to the entities that own them, and the code-generation modules don't support it. Such an association is shown as a validation error on the Value Object:

Value Object 'Address' cannot be associated to Entity 'Country'. Value Objects can only be associated to other Value Objects.