Compositional
model
An
ideal reuse technology provides components with standard interfaces that
can be easily connected to make a new system. Software developers
do not have to know the internal implementation of a component,and it is
easy for them to learn how to use it. However, components are not isolated
entities, they usualliy interact with others to achieve their computation.
Therefore, we should distinguish between how a component achieves its computation
and how that computation is combined with others in the overall system.
The first
challenge was the definition of a new composition model that separates
computation form coordination. The compositional units of the model are
the component that encapsulates computation , and the connector that encapsulates
a coordination protocol. Connections between components and connectors
define the architecture of an application and are governed by a set of
plug-compatibility rules. In addition, this model defines a dinamic binding
mechanism that plugs components into connectors at runtime. In consequence,
the compositional model defines a new dsign pattern that will be the base
technology for an application framework.
The
model is based in the following proposition:
Open
Systems = Components + Coordination