The Approach - Model Driven Architecture using Executable UML

The use of MDA allows the mission software functionality to be formalised as Executable UML models (xUML); such models are Platform Independent Models (PIM) in MDA. Platform independence is essential if the goal of decoupling the models from any changes to the Software Execution Platform is to be achieved. xUML models are expressed using a UML action language based on the newly adopted precise action semantics for the UML.

Executable models support the MDA approach in two main ways. First, they allow early testing using simulation and debug tools. Secondly, since they are a full and formal specification of the system behaviour, they allow generation of the target code. Defining a mapping from the rigorously defined PIM (expressed in xUML) to the implementation is what is at the heart of MDA. Since xUML models are executable and rigorous they act as much more than a simple visual agenda for the software developers, they actually embody all the business logic required to execute and verify the system.

Figure 2 - Lockheed Martin's MDA process