[kepler-dev] programatic access to class entity

Shawn Bowers sbowers at ucdavis.edu
Wed Jul 27 09:17:12 PDT 2005

Hi Edward,

Just out of curiosity, how do you track instances across multiple MoML 
files? For example, if I define a class and store it in a particular 
MoML file, then instantiate the class in multiple workflows (each stored 
in a different MoML file), and I make a change to the original class, 
how does this change propagate to the various instances?  Or, is a class 
only identified within a particular context?

It sounds like you say below that "any changes" made to the class will 
be made to all the instances; so knowing how you track this would be 
potentially useful to some of the Kepler implementations of KSW, etc.


Edward A. Lee wrote:
> The <class> tag is defined in section 2.7 of vol. 1 of the Ptolemy II docs.
> An entity that is defined as a <class> can be instantiated many times,
> without copying its contents. Any changes made to the class will be made
> to all the instances. It can also be subclassed.
> We call this mechanism "actor-oriented classes" to distinguish them
> from the "object-oriented classes" of Java.  It brings the OO concept
> of inheritance to actor-oriented designs.  There is a paper on it
> at:
> http://ptolemy.eecs.berkeley.edu/publications/papers/04/Classes
> Edward
> At 03:20 PM 7/20/2005 -0700, Chad Berkley wrote:
>>does anyone know what the programatic difference is between an entity
>>that is defined in moml as <entity> vs. one that's defined as <class>?
>>I need to figure out the difference in the KSW builder, but i can't see
>>where in the MoML API you can get information as (AFAICT) they both get
>>instantiated as a ComponentEntity.  Basically, i just want to know how
>>to tell the difference (programatically) between a stand alone workflow
>>and a moml based composite actor.
>>Kepler-dev mailing list
>>Kepler-dev at ecoinformatics.org
> ------------
> 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  
> _______________________________________________
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