A value transfer is used to connect two value ports with each other. It shows the actors, who are willing to transfer value objects with each other. Transferring value objects means a change in rights. In case of physical goods, the most important right is ownership, in case of services, the right is to experience a service outcome.
In the figure below ‘money’ is transferred from the ‘traveler’ to the ‘railway company’. This transfer is named ‘payment’, representing that the ‘money’ is used as a payment for other objects delivered. Other transfers are ‘food’ and ‘train trip’.
|Name||The name reffects the kind of role the transfer plays while transferring a value object. For instance, a value object ‘money’ usually has the role ‘payment’.|
|Cadrinaltity||The cardinality property models that a number (given by the cardinality) of value objects are exchanged via the same transfer, rather than just one value object. In case one of the value ports the transfer connects to has also a cardinality stated, the cardinality of the transfer overrules the cardinality of the port, for that transfer. So, in case a port indicates that three ‘hamburgers’ should be obtained, and the related transfer indicates only two ‘hamburgers’, these two ‘hamburgers’ are transferred for the considered transfer, and not three. Note that the stated cardinality at the port provides a ‘default’ value, for all transfers that do not have a cardinality property.|
The value ports involved in a value transfer are represented
by the has in and has out relations, which relate to exactly
one in-port and exactly one out-port. A value port may connect
to zero or more value transfers. This is because an actor may decide
to choose from a set of actors (each having value transfers
with the actor at hand).