Delegation connectors can be of two types: provided delegation connectors and required delegation connectors. Provided delegation connectors connect one outer provided role (without context) with one inner provided role in context of a composite component. This composite component has to provide the outer role. The inner provided role in context needs to be one of an inner component (contains-relation). Figure 3.9 illustrates a valid delegation connector (between IA and Component A) and an invalid delegation connector (between IB and Component B).
The outer provided role is connected without a context usage of the composite component. This implies that for every context instance of the composite component the connector applies to the outer provided role in context, too. The reason for this is the fact that composite components are component types, while the inner realisation of composite components are a kind of component usage. Inner components of a composite component stem from a component repository, and so they are components in context.
The case for required delegation connectors is quite alike. One inner required role in context is connected with one outer required role.
A signature-mapping in terms of an adapter (see [24,25]) is not possible for delegation connectors: they usually map interfaces 1:1. If a signature-mapping is required, an adapter component needs to be introduced. This separate component would do the adaption.
There are some differences in the PCM to what the UML suggests. The UML visualizes delegation connectors as dashed arrows, that indicate the direction of delegation. The line connects an outer with an inner interface. However there are two interfaces connected, in terms of the PCM in fact the roles in context are meant, which are associated with the interfaces.