[kepler-dev] [reap] Automatic output port generation in RecordDisassembler

[Dan Higgins]

Hi James,
    Without looking at the code details, I was assuming that the OpenDAP 
actor does just what you stated - get information from the net at design 
time and (perhaps) at run time. I know the EML datasource gets the EML 
metadata at design time to build output ports.

Dan

James Gallagher wrote:
>
> On Nov 15, 2007, at 12:14 PM, Dan Higgins wrote:
>
>> Hi Ilkay,
>>     I got thinking about this issue after our last REAP call and thought
>> I would try to summarize some thoughts here.
>>
>>     At design time, actors are really independent. Most of the actors
>> that dynamically generate output ports are data source actors. Except
>> for trigger inputs, there are no inputs and the output ports can be
>> generated because the actor uses some parameter to get the data needed
>> to generate ports when it is instantiated (i.e. dropped on the canvas)
>> or input parameters are changed. [Example: EML2 Datasource uses the eml
>> metadata, the OpenDAP actor uses a URL; Changing an actor parameter
>> during design will trigger changes in the output ports due to
>> AttributeChanged events.]
>>
>
> [snip]
>>
>>     So all this brings me to one possible solution. Assume that any data
>> source that actually gets information at design time (like the EML of
>> the EML actor or the OpenDAP actor) ALSO created a Kepler parameter when
>> it was dropped on the canvas (or its parameters were changed) and this
>> new parameter were automatically made visible on the workspace canvas.
>> The parameter would basically be the schema of the Record or EML that
>> the actor might output. Any other actor added to the model could then
>> use that parameter. e.g. if the parameter were a Record, a
>> RecordDisassembler could use it as a template for creating outputs.
>>
>> Comments and discussion always appreciated.
>
> Dan, if we assume that an actor for opendap has, at design time, a URL 
> to a data source and that the network is available, then that actor 
> could request the DAP DDS or DDX object and get this information. Is 
> that what you're thinking about? If so, one way to characterize it 
> might be that the actor needs 'syntactic metadata' at design time.
>
> Conclusion: To do this in general we need a network and data transfer 
> both when the workflow is run and also at the time the workflow is 
> designed.
>
> I'm not sure if that's what you said or an an extension...
>
> James
>>
>> Dan
>>
>> ----
>>
>>
>>
>> Ilkay Altintas wrote:
>>> Hi,
>>>
>>> I'm interested in generating a RecordDisassembler that can get the
>>> names of the record parts from the downstream actor and create its
>>> output ports automatically.
>>>
>>> Currently this is not possible as the data type for the record input
>>> port is unknown until run time. I was wondering if there is a quick
>>> method where I can get it to have the information I need to create
>>> the ports by invoking a method at design time. Or do you know a
>>> better way to implement this?
>>>
>>> Any help would be appreciated...
>>>
>>> Thanks!
>>> -ilkay
>>>
>>>
>>> _______________________________________________
>>> Kepler-dev mailing list
>>> Kepler-dev at ecoinformatics.org
>>> http://mercury.nceas.ucsb.edu/ecoinformatics/mailman/listinfo/kepler-dev 
>>>
>>>
>>>
>>
>>
>> -- 
>> *******************************************************************
>> Dan Higgins                                  higgins at nceas.ucsb.edu
>> http://www.nceas.ucsb.edu/    Ph: 805-893-5127
>> National Center for Ecological Analysis and Synthesis (NCEAS) Marine 
>> Science Building - Room 3405
>> Santa Barbara, CA 93195
>> *******************************************************************
>>
>> _______________________________________________
>> reap mailing list
>> reap at ecoinformatics.org
>> http://mercury.nceas.ucsb.edu/ecoinformatics/mailman/listinfo/reap
>
> -- 
> James Gallagher                jgallagher at opendap.org
> OPeNDAP, Inc                   406.723.8663
>
>
>


-- 
*******************************************************************
Dan Higgins                                  higgins at nceas.ucsb.edu
http://www.nceas.ucsb.edu/    Ph: 805-893-5127
National Center for Ecological Analysis and Synthesis (NCEAS) Marine Science Building - Room 3405
Santa Barbara, CA 93195
*******************************************************************