RTC — Data flow diagrams

Summary

Like Figure 7.2 Lightweight RTC package,I think it would be better that Figure 7.6 Data flow type be divided into several diagrams.

In terms of the Stereotype description, dataFlowComposite (Page 33) and dataFlowParticipant (Page 35), since there is a description, "The dataFlowComposite stereotype may only be applied to a component that is also extended by the lightweightRTComponent stereotype or some subtype thereof" in Constraints, I think it would be better to take over the lightweightRTComponent stereotype. If lightweightRTComponent is taken over, the stereotype that takes over the characteristics of lightweightRTComponent is only one, either dataFlowComposite or dataFlowParticipant, and the description in Constraints can be deleted.

Proposed Resolution

[attachment:data-flow-metamodel.png] [[BR]] Meta-Model

[attachment:data-flow-stereotypes.png] [[BR]] Stereotypes

Discussion

I agree with the reorganization of the diagrams. I'm not sure about the stereotypes, though. By "take over the lightweightRTComponent stereotype," you mean define dataFlow* as subtypes of lightweightRTComponent? I think there may be a problem with that when multiple stereotypes are used. If a component has both dataFlowParticipant and dataFlowComposite, the lightweightRTComponent stereotype will really be there twice. I don't know whether that's a problem in UML, but when it is mapped to IDL and then to code, it will result in diamond inheritance, which can be inconvenient.

– RickWarren, 2006/11/27

Sakamot-san's comment.

Although two stereotypes have inheritance relation in stereotypes definition, they need not have inheritance relation in implementation.

• The stereotype definition defines how the meta-class (in our case, it is Component) should be extended.
• The inheritance (or generalization) makes the feature that is defined in the upper-class take over to a lower-classes as it is.
• According to the stereotype inheritance, the lower-classes can use extension method that is defined in upper-class.

Since the stereotype defines only meta-classes extension, it does not limit implementation or PSM.

– NoriakiAndo, 2006/12/4

Unify the dataFlowParticipant and dataFlowComposite stereotypes. The combined stereotype will extend the lightweightRTComponent stereotype directly.