The script would need to address component-specific interface peculiarities for both integrated components. Thus, the external agent-shell script would not be a wrapper, in our definition, because it would address the interfaces of both endpoints of the integration relation. Alternatively, either component could launch the filter. In this case, the repair mechanism would involve a hybrid wrapper and filter. The wrapper would invoke the repair code necessary to detect the need to launch the bridge and to launch it.
Mediators exhibit properties of both bridges and wrappers.
Mediators are also similar to wrappers insofar as the mediator becomes a more explicit component in the overall software architecture. That is, semantically primitive, often transient, bridges can be thought of as incidental repair mechanisms whose role in a design can remain implicit. Mediators are a speculative and less explored technique than either bridges or wrappers. To illustrate mediators, we focus on the runtime planning function of mediators because this is the key distinction between mediators and bridges. One scenario that illustrates mediation is intelligent data fusion.