Keywords: MiddleWG
Hi UMLers,
At our middleware videocon, I took on an action to press on some use cases
that elucidate how the Data Access Framework works its magic. A main
focus will be on the case of cross-talk correction. I am putting together
a problem statement will help scope what robust diagrams, for example,
need to be generated to illustrate this. I feel this needs to be put in
terms of the UML use cases and should perhaps include robustness diagrams
for related components that help support the context. While working my
way through this, I found the need to make (what I hope are) small
changes to the UML model. This message describes the first set of changes
which I just checked in.
This set of changes appear in the Processing Framework Summary diagram in
the Framework package of the Domain Model. The main change is a shift in
the definition of a Job. Previously, this was defined to be something
that controls an instance of a Pipeline and scheduled by a Job Scheduler.
I have shifted the defintion of a Job to be the instantiation of a
*Processing Step*. The latter represents the unit of processing that is
actually scheduled and executed as a whole. The various processing steps
could be scheduled on different platforms (say, one step requires a
shared-memory platform). With this shift, I felt we now needed to show a
class that instantiates and manages a Pipeline as a whole, so I added a
"Pipeline Manager" class.
To give you a sense of why I felt this necessary, I'll point out that the
model for parallelism for the cross-talk correction may be different that
that of the rest of the Calibration Pipeline. I wanted to allow, if it
turns out to be useful, the option of separating this correction into its
own processing step apart from the other stages of calibration (which
could require a shifting of data by the DAF). In this case, I feel we
need to show a little more clearly how processing steps are scheduled and
managed as individual entities.
In summary, my changes were:
o shifted defintion of Job to be a scheduled instance of a Processing
Step.
o added Pipeline Manager class which contols a Pipeline and invokes a
Job Scheduler to shedule Jobs that carry out the Pipeline's work.
o added defintions (in the Notes Section) to key classes in the diagram
(attn: Jacek--including Provenance objects; please verify).
o rearrange visual layout accordingly.
cheers,
Ray
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