[kepler-dev] difference between moml class and entity

[Edward A. Lee]

The way the library works is that when you drag something into
a model, the entity in the library is treated as a template.
The drag-and-drop code asks the template to exportMoML(), and
then interprets that MoML in the context of the drop destination.
Thus, if the template is a class, then you will get a class
in the drop destination.  If the template is an instance, then
you will get an instance.

The Sinewave actor in the library is an instance of a class
defined in a separate file. In the library it is defined as:

<entity name="Sinewave" class="ptolemy.actor.lib.Sinewave"/>

There is a file $PTII/ptolemy/actor/lib/Sinewave.xml that contains

<class name="Sinewave" extends="ptolemy.actor.TypedCompositeActor">
  ...
</class>


Hope this helps...

Edward

At 03:08 PM 12/9/2005 -0800, Chad Berkley wrote:
>exportMoML() is what i meant by serialize.  When i'm adding a moml class 
>to the library, i get a class exported, but that seems problematic because 
>the class is actually an instance (if that makes any sense). The question 
>i've been wondering about is, why is Sinewave declared (in the actor 
>library) as an entity when it is, in fact, defined as a class (in it's 
>moml definition); and how can i programatically do that if that is 
>required to create an instance?
>
>I feel like i'm missing something here, but I'm not sure what.
>
>chad
>
>Edward A. Lee wrote:
>>
>>I'm confused... What do you mean by "serialize"?
>>If I do exportMoML() on an instance, I will get an instance.
>>If I do exportMoML() on a class, I will get a class...
>>Seems right to me...
>>Edward
>>
>>At 10:24 AM 12/9/2005 -0800, Chad Berkley wrote:
>>
>>>Hi,
>>>
>>>I've run into a problem when trying to differentiate whether a composite
>>>should be serialized to moml as a <class> or as an <entity>.  In PTII, a
>>>Composite is defined as a <class> within its own moml file.  Take
>>>Sinewave (ptolemy/actor/lib/Sinewave.xml) for example:
>>>
>>><class name="Sinewave" extends="ptolemy.actor.TypedCompositeActor">
>>>....</class>
>>>
>>>However, within the actor library CompositeEntity, Sinewave is refered
>>>to as an entity (/ptolemy/actor/lib/sequencesources.xml):
>>>
>>><entity name="Sinewave" class="ptolemy.actor.lib.Sinewave"/>
>>>
>>>Programmatically, if I serialize Sinewave's moml, the momlParser returns
>>>a class element.  This is problematic because I'm altering the actor
>>>library programmatically.  When I do a
>>>Sinewave.setContainer("actorLibrary"), it serializes as a class.  This
>>>wouldn't be bad, except that when you drag it onto the canvas, it is
>>>then interpreted as a class that needs to be instantiated instead of as
>>>an instance (i.e. the purple box is drawn around it).
>>>
>>>Is there a way to tell it to give me the instance moml instead of the
>>>class moml?
>>>
>>>thanks,
>>>chad
>>>_______________________________________________
>>>Kepler-dev mailing list
>>>Kepler-dev at ecoinformatics.org
>>>http://mercury.nceas.ucsb.edu/ecoinformatics/mailman/listinfo/kepler-dev
>>
>>------------
>>Edward A. Lee
>>Professor, Chair of the EE Division, Associate Chair of EECS
>>231 Cory Hall, UC Berkeley, Berkeley, CA 94720
>>phone: 510-642-0253 or 510-642-0455, fax: 510-642-2845
>>eal at eecs.Berkeley.EDU, http://ptolemy.eecs.berkeley.edu/~eal

------------
Edward A. Lee
Professor, Chair of the EE Division, Associate Chair of EECS
231 Cory Hall, UC Berkeley, Berkeley, CA 94720
phone: 510-642-0253 or 510-642-0455, fax: 510-642-2845
eal at eecs.Berkeley.EDU, http://ptolemy.eecs.berkeley.edu/~eal