A Block stereotype extends Class so it can be applied to any specialization of Class including Association Classes. Association Classes are informally called “Association Blocks.” An Association Block can own properties and connectors just like any other Block. Each instance of an Association Block can link together instances of the end Classifiers of the Association. To refer to the linked objects and values of an instance of an Association Block, it is necessary for the modeler to specify which (participant) properties of the Association Block identify the instances being linked at which end of the Association. The value of a participant property on the instance (link) of the Association Block is the value or object at the end of the link corresponding to this end of the Association.

The following figures depict the use of an Association Block in a model.


System initializes «ConnectorProperty» by an Association Block instance according to "Connector" reference (AB) and «ParticipantProperty» (b2, b1. add. b21. b11) according to "End" reference (b1, b2).

An Association Block can provide or add anything such as Behaviors and connectors (a, b) so signals can flow. Parametric and all other constraints (a = b + 5) work automatically.