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JWT Metamodel Extension Specifications/Technical Specifications v1

Introduction

Building on all that has been said, here is my proposition.

Its strong points are

  • it unifies the simple, static EMF DynamicProperties and the powerful, EMF-extensible Aspects solutions
  • once the model has been defined, functionnalities can be added step by step, meaning it will be usable from day 1, and we can add other features (like using visibleOnChildren to impact the outline and property page UI behaviour, or loading externally defined profiles in JWT, or code handling extension versioning check) later, when we are sure of them and when we have time. I'll outline this here by "LATER".

It relies on two concepts :

  • aspect (or dynamicproperty) : a single typed extension of a model element
  • profile (or DynamicPropertyContainer, or ModelExtension) : a model extension made of a consistent collection of aspects

It has been filed in bugzilla as bug 241567 "Typed metamodel extensions (Aspects)" (see https://bugs.eclipse.org/bugs/show_bug.cgi?id=241567 ).


Metamodel specification

ProfileDefModel metamodel

  * done in static EMF
  * contained in Model or / and independent XMI file, which could be the same as the new Views one

ProfileDefModel :

profiledefs : ProfileDef *

ProfileDef :

name
description
author
version
JWT version (modelversion ?)
aspectdefs : AspectDefs *

AspectDef :

id (jwt type) (string, reference ??)
etype (those extending Aspect are aspects, the others e.g. primitives or EObject are supported using Property) : EString
singleton : EBoolean
assignedto (? EClass but requires to refer to the ecore, or EString)
visibleAsChild : EBoolean


JWT metamodel

  * depends on the static ProfileDefs metamodel

Model

profiledefs : ProfileDefs

ModelElement :

aspects : Aspect *

Aspect :

id (jwt type)

Property extends Aspect :

value : EObject


Simple Property Example

Now an example of properties (csaad's) :

  * an instance of ProfileDef (name="Example1")
  * containing an AspectDef (name=id="internal_id1", etype="EString", assignedto="Action", singleton="true")
  * and another AspectDef (name=id="internal_id2", etype="EInteger", assignedto="ActivityNode", singleton="true")

Which automatically creates property instances under said model elements, for example :

  * an instance of JoinNode (name="node1") containing an instance of Property (name=id="internal_id2", value="intvalue1")
  * an instance of ActionNode (name="node1") containing an instance of Property (name=id="internal_id2", value="intvalue2") and another instance of Property (name=id="internal_id1", value="stringvalue1")


Extended Model Example

Now an example of an extended model :

  * an instance of ProfileDef (name="BonitaProfile")
  * containing an AspectDef (name=id="BonitaTaskAspectDef", etype="BonitaTaskAspect", assignedto="Action", singleton="false")
  * which makes BonitaTaskAspect available to be created under Action,
  * BonitaTaskAspect being defined as such :

BonitaTaskAspect :

bonitahooks : BonitaHook*

BonitaHook

event : EString (listbox)
javaClass : EString
jar : EString


Original DynamicProperty Metamodel

Note : csaad's was :

ModelElement :

properties *

DynamicPropertyContainer :

name
description
author
version
JWT version
dynamicproperties *

DynamicProperty :

id
type (of value ?)
assignedto
visibleOnChildren (?)


Features

Localization :

  * Names displayed in the UI (such as those of Property instances) have to be localized. It should be done in the Eclipse manner, using bundles, and if necessary a bit of our code. However I don't think we should put localized names in the model.

Managing the model :

  * Configuration : Which profiles among the ones loaded in JWT are activated in a given workflow model ?
     * all those explicitly defined in this workflow model,
     * LATER and all those in files configured in plugin.xml .
     * LATER buttons allowing to save a workflow containg all profile definitions (including JWT configured ones)
  * Versioning :
     * updating existing version check code so it works with the new model
     * updating existing version check code so it works with the extended EMF metamodels
     * LATER adding profile versioning check

UI

  * LATER Property / Outline : according to visibleAsChild, Aspect instances's content (including Property instances' content) will be either shown as a subelement of their assigned model element instance, or merged in the assigned model element instance's property page. Proposition : this property page's layout could separate each Aspect content by bars.
  * LATER in the outline, commands for creating "not singleton" aspects ; and forbidding deletion of "singleton ones".
  * LATER in the outline, finer extensibility of the "new Child" commands, including allowing to configure in plugin.xml commands that create a type with a given set of aspects.
  * LATER Diagram : nothing

Transformation

  * LATER define an extension point on transformation allowing to specify additional transformation rules for a given profile (not sure of this one, typed profiles sure are nice for this, but has to be tried first).

Packaging

  * LATER Using EMF.Edit, create a simple editor for the ProfileDefModel metamodel and make it available in the jwt packaging tool

Finding and loading extension

  * LATER static EMF extension models can be configured in plugin.xml to be loaded
  * LATER dynamic EMF extension ecores can be provided in given directory to be loaded