[SAGA-RG] spec

[Andre Merzky]

Quoting [Ceriel Jacobs] (Dec 13 2007):
> 
> Andre Merzky wrote:
> >Quoting [Ceriel Jacobs] (Dec 13 2007):
> 
> >>But, I just noticed another one: in the monitoring package, metric class,
> >>there is a sentence that states that
> >>
> >>    The metric |type|s are the same as defined for attributes,
> >>    and the metric |value|s are to be formatted as described for
> >>    the respective attribute types.
> >
> >Ah, well, finite + n ... ;-)
> >
> >>But what about the Trigger type? This is not mentioned as one
> >>of the attribute types. In fact, it is never really specified what
> >>a 'Trigger' is.
> >
> >Ah, good one, will fix that.  In short: 'Checkpoint' would
> >be a good example for a trigger.  Its not boolean: you never
> >notify an application 'Do no checkpoint now!' - but you use
> >the metric to trigger a checkpoint 'Checkpoint now!'.  I
> >guess this is equivalent to an attribute who's existence or
> >absence carries semantic meaning (e.g. 'Checkpointable').
> >That, however, maps pretty nicely to boolean attributes in
> >all cases I can think of ('Checkpointable=yes').
> 
> I think a Trigger is a metric that has no value (or just a single
> value) but that may get fired (read: the registered callbacks are
> called). This indeed maps nicely to boolean attributes,
> with a "fire" when the value changes to "true".
> But I also think the value is immaterial.
> Maybe the getAttribute("Value") method should throw an exception
> when the metric is of type "Trigger"?
> Then you don't have to think about the attribute type of a "Trigger".

Good point, the actual value is indeed immaterial.  Will do
that, thanks!

Andre.


> Ceriel



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