Replaces Variability Associations

Replaces variability association provide a mechanism for an element to replace a base element without directly changing any of the base element's existing properties. A replacing element replaces relevant attributes in the base element when the configuration is published or examined in the Browsing perspective. In most cases this is used for method plug-ins as a way to replace specific content elements such as roles, tasks, or activities with either a completely new variant. Replacement can also be used to change the fundamental relationships of these elements. The base content element will be logically replaced with the new replacing element to which all incoming associations still point as before, but which has potentially new attribute values and outgoing associations.

When you replace an element, all the description attributes are replaced by corresponding attribute values from the replacing element. If a description attribute in the replacing element is blank but the base element has content, the attribute will be blank in the resulting element.

Replace always replaces attributes and associations of the base element with the replacing element's attributes and associations, except for incoming associations, which are only added to the base, but do not replace the base's incoming associations.

Replace Association Rules:

Outgoing associations are not affected.
Incoming associations from the base element are added to the replacing element.
Attributes of the base element are replaced with attributes of the replacing element including the base element's identifier.
A base element of a replacement can have only one replacing element per configuration. If more than one replacing element is present no replacement takes place.
Replacement is transitive. If a replacing element is replaced itself the final replacer prevails.
Contribution precedes Replacement. Contribution associations are resolved first and then replacement is performed afterwards. The evaluation of contribution and replacement is performed in serial order in the specialization hierarchy.

Exceptions

All replacing associations are "many to many" except for the following:

Task elements can have only one association to the Primary Performer Role. There is no exception when replacing a Task or a Role.
Work Products can only be assigned to a single Domain. If the replacing Work Product is assigned to a Domain the relationship from the base is ignored. There is no exception when replacing a Domain element.
Tool Mentors can only be assigned to a single Tool. If the replacing Tool Mentor is assigned to a Tool the relationship from the base is ignored. There is no exception when replacing a Tool element.

See Associations Impacted by Variability for more information on the associations for each element type.

How to Add a Replace Association

Use the Content Variability section on the Description tab to make an element replace another element.
Select Replaces as the variability type and select the base element that this element will replace. Note that the base element must be the same type of element as the replacing element.