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(Metamodel extensions and JWT WE (added 20080527))
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== Introduction ==
 
== Introduction ==
 +
This page describes the architecture, requirements and discussions for the meta-model of JWT. Starting from the original meta-model of AgilPro, it  summarizes all evolutions, extensions, wishes etc.
  
This page describes the discussions and requirements for the meta-model of JWT. Based on the existing meta-model of AgilPro we will summarize all wishes, extensions etc. on this page.
 
  
An important part is JWT metamodel's extensibility.
+
== Architecture and governance ==
 +
The JWT metamodel comprises
 +
* a core workflow metamodel that is as generic as possible
 +
* extensions that allow to provide specific additional features
 +
* overall governance that allows extensions to coexist within the JWT ecosystem.
  
 +
=== Core metamodel ===
 +
Its aim is to be a workflow metamodel that is as generic as possible.
  
== Initial metamodel ==
+
Changes to the core metamodel should rather go in metamodel extensions, because they affect possibly all JWT users and must therefore be considered very carefully.
  
This document [[Image:AgilPro_MetamodelDescription.pdf]] describes the metamodel of AgilPro as it is today (2007-02-21). This document will be the basis for discussions on all working groups who have requirements on the meta-model.
+
=== Metamodel extensions ===
 +
Metamodel extensions allow to provide specific additional features, be it UI like JWT views, runtime like a WebServiceApplication or other features like logging.
  
== JWT metamodel comparisons ==
+
* Official JWT metamodel extensions : an official JWT metamodel extension is the standard for its domain model. To make your metamodel extension official, there must be none yet for its domain model, it must be approved by project leads and listed in [[JWT Metamodel Extensions/Official]]
 +
* JWT Labelized metamodel extensions : if there is already an official JWT extension for your domain model, you can make it JWT labelized by implementing a two-way transformation to an existing official or labelized metamodel extension along with its transformation documentation and test kit, make it approved by project leads and list it in [[JWT Metamodel Extensions/Labelized]]
 +
* extensions can obviously still be developed by anyone without being official or labelized, though their users can't be sure they'll be able to freely benefit from other parts of the JWT ecosystem, because of possible domain model specific incompatibility.
  
=== Comparison with other metamodels ===
+
=== Metamodel evolution ===
A comparison with other meta-models as a result of an evaluation can be found in the following document: [[Image:EvaluationExistingMetamodels.pdf]].
+
In order to become better and answer more user requirements, the JWT metamodel evolves. In order to avoid conflicts and compatibility problems, it does so in a governed manner, and with the help of tools such as an automated version converter.
  
 +
Metamodel Roadmap
 +
* initial metamodel : JWT up to 0.5 . This was originally AgilPro's metamodel.
 +
* aspect extensions : JWT 0.6 . Includes core metamodel improvements and the new aspect extension mechanism.
 +
* externalized metamodel : JWT 0.7 The metamodel will be in its own plugin.
 +
* small improvements are expected for the next version.
  
=== Metamodel and XPDL 1.0 ===
+
== About JWT up to 0.5 and AgilPro metamodel ==
  
The document [[Image:AgilPro_Metamodel.pdf]] describes an initial revision of the document comparing the JWT/AgilPro metamodel with the XPDL 1.0 schema.
+
As said in the Roadmap, the metamodel has since changed so the following is not up to date, but still mostly valid.
It covers all the XPDL elements as well as the Bonita engine vendor specific extensions.
+
  
=== Metamodel and BPMN ===
+
=== Design ===
 +
This document [[Image:AgilPro_MetamodelDescription.pdf]] describes the metamodel of AgilPro as it was of 2007-02-21. This document has been the basis for discussions on all working groups who have requirements on the meta-model.
  
Please find under [[Image:Comparison_JWT_BPMN_v0_3.pdf]] a document describing the differences between the JWT Metamodel on the one hand and BPMN on the other.
+
=== Metamodel comparisons ===
  
 +
==== JWT Metamodel and XPDL 1.0 ====
 +
The document [[Image:AgilPro_Metamodel.pdf]] describes an initial revision of the document comparing the JWT 0.5/AgilPro metamodel with the XPDL 1.0 schema.
 +
It covers all the XPDL elements as well as the Bonita engine vendor specific extensions.
  
== [[JWT Metamodel Extension Specifications]] ==
+
==== JWT 0.5 Metamodel and BPMN ====
* [[JWT Metamodel Extension Specifications]]
+
The document [[Image:Comparison_JWT_BPMN_v0_3.pdf]] describes the differences between the JWT 0.5 Metamodel on the one hand and BPMN on the other.
 
+
 
+
== [[JWT Metamodel Extension Specifications/Requirements|Extension Requirements and Use Cases]] ==
+
 
+
== [[JWT Metamodel Extension Specifications/Alternatives Study|Specification Alternatives Study]] ==
+
 
+
== [[JWT Metamodel Extension Specifications/Prototype|Metamodel Extension Prototype]] - working samples (added 20080527) ==
+
 
+
== [[JWT Metamodel Extension Specifications/WE|Metamodel extensions and JWT WE (added 20080527)]] ==
+
 
+
== [[JWT Metamodel Extension Specifications/Transformations|Metamodel extensions and JWT Transformations]] ==
+
TODO
+
 
+
== [[JWT Metamodel Extension Specifications/Runtime|Metamodel extensions and JWT Runtimes]] ==
+
TODO
+
 
+
 
+
== [[JWT Metamodel Extension Specifications/Technical Specifications v1|Technical specifications v1]] ==
+
 
+
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 ===
+
==== JWT 0.5 Metamodel and various others ====
Localization :
+
A comparison with other meta-models (including BPM Guide's Simple BPM, BPDM, AgilPro, UML Activity Diagram, Event-driven Process Chains, List/Korherr's  metamodel) as a result of an evaluation can be found in the following document: [[Image:EvaluationExistingMetamodels.pdf]].
  * 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 :
+
== Extending the JWT Metamodel ==
  * Configuration : Which profiles among the ones loaded in JWT are activated in a given workflow model ?
+
Extending the JWT Metamodel is necessary as soon as you need to enrich your model with custom information, for example information that is specific to your business or to your runtime execution platform.
      * 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
+
JWT's Metamodel is based on EMF, for which there are several ways to add custom information, that are analyzed at [[JWT_Metamodel_Extension#EMF_model_extension_alternatives]] . Two ways are available out of the box in JWT :
  * 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.
+
* '''1. "classical" EMF extension''' : extend an existing type of the model with your own type. This is only interesting to create well identified subtypes, i.e. that could have been provided in the base model beforehand. If it is the case, please consider contributing it to JWT's core metamodel.
  * LATER in the outline, commands for creating "not singleton" aspects ; and forbidding deletion of "singleton ones".
+
* '''2. EMF Aspects extension''' : manage instances of your own types in another model that let them refer to the main model's elements. This non-intrusive solution works with any model without prerequisite and allows to share type extensions between model types. In JWT, Aspects do this in a simple, typed way that allows for having custom-information coming from different third-party providers, while the genmodel file is a more complex example.  
  * 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
+
=== 1. "classical" EMF extension ===
  * 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).
+
* 1. define the EMF model
 +
* 2. To enable EMF child extenders, extensibleProviderFactory="true" has to be set on the genModel package of the EMF class you want to extend, and on your side you have to set childCreationExtenders="true" on the genModel package of your extending EMF class. See an example in jwt-we-plugins/jwt-we-sample-aspectchildextenders and Ed Merks' blog at http://ed-merks.blogspot.com/2008/01/creating-children-you-didnt-know.html
 +
* 3. create a new FactoryRegistry and override the Palette (or create new Palette)
 +
* 4. in Palette just add new model item ex. activityGroup.add(createCreationToolEntry(ModelPackage.Literals.TRANSPORT_OBJECT))
  
Packaging
+
(courtesy of Kim Nguyen and a lot of others)
  * 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
+
=== 2. JWT Metamodel EMF Aspects 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
+
  
 +
==== Using JWT Metamodel Aspects Extension ====
 +
[[JWT_Metamodel_Extension]] documents how to use store custom information in (workflow) models using Conf, Profiles and Aspects :
 +
* prerequisites : [[JWT_Metamodel_Extension#Using_aspect_model_extensions|Using aspect model extensions]]
 +
* [[JWT_Metamodel_Extension#Creating_custom_aspect_model_extensions|Creating custom aspect model extensions]]
 +
** [[JWT_Metamodel_Extension#Setting_up_simple_.28key-value.29_additional_model_extensions|Setting up simple (key-value) additional model extensions]] thanks to the jwt-we-conf-property official JWT metamodel extension
 +
** [[JWT_Metamodel_Extension#For_advanced_users_:_designing_complex_additional_model_extensions_without_code|For advanced users : designing complex additional model extensions without code]]
 +
** [[JWT_Metamodel_Extension#For_developers_:_developing_complex_additional_model_extensions_using_EMF-generated_code|For developers : developing complex additional model extensions using EMF-generated code]]
 +
* For other EMF-based tool developers: [[JWT_Metamodel_Extension#For_other_EMF-based_tool_developers_:_enriching_a_model_with_extensions|allowing aspect extensions in an EMF model]]
 +
* [[JWT_Metamodel_Extension#Aspect_model_extension_samples|Summary of all Aspect model extension samples]]
  
== [[JWT Metamodel Extension Specifications/Technical Specifications v2|Technical specifications v2]] ==
+
==== (for JWT developers only) Design and development of Aspects metamodel extension feature ====
See bugzilla https://bugs.eclipse.org/bugs/show_bug.cgi?id=241567 .
+
* Development : See bugzilla https://bugs.eclipse.org/bugs/show_bug.cgi?id=241567
 +
* Design : [[JWT Metamodel Extension Specifications]] describes the initial specifications of the aspects metamodel extension mechanism :
 +
** [[JWT Metamodel Extension Specifications/Requirements|Extension Requirements and Use Cases]]
 +
** [[JWT Metamodel Extension Specifications/Alternatives Study|Specification Alternatives Study]]
 +
** [[JWT Metamodel Extension Specifications/Prototype|Metamodel Extension Prototype]] - working samples (added 20080527)
 +
** [[JWT Metamodel Extension Specifications/WE|Metamodel extensions and JWT WE (added 20080527)]]
 +
** [[JWT Metamodel Extension Specifications/Transformations|Metamodel extensions and JWT Transformations]] - TODO
 +
** [[JWT Metamodel Extension Specifications/Runtime|Metamodel extensions and JWT Runtimes]] - TODO
 +
** [[JWT Metamodel Extension Specifications/Technical Specifications v1|Technical specifications v1]] (obsolete)
 +
** [[JWT Metamodel Extension Specifications/Technical Specifications v2|Technical specifications v2]] - See bugzilla https://bugs.eclipse.org/bugs/show_bug.cgi?id=241567 .

Latest revision as of 09:45, 20 August 2010

Introduction

This page describes the architecture, requirements and discussions for the meta-model of JWT. Starting from the original meta-model of AgilPro, it summarizes all evolutions, extensions, wishes etc.


Architecture and governance

The JWT metamodel comprises

  • a core workflow metamodel that is as generic as possible
  • extensions that allow to provide specific additional features
  • overall governance that allows extensions to coexist within the JWT ecosystem.

Core metamodel

Its aim is to be a workflow metamodel that is as generic as possible.

Changes to the core metamodel should rather go in metamodel extensions, because they affect possibly all JWT users and must therefore be considered very carefully.

Metamodel extensions

Metamodel extensions allow to provide specific additional features, be it UI like JWT views, runtime like a WebServiceApplication or other features like logging.

  • Official JWT metamodel extensions : an official JWT metamodel extension is the standard for its domain model. To make your metamodel extension official, there must be none yet for its domain model, it must be approved by project leads and listed in JWT Metamodel Extensions/Official
  • JWT Labelized metamodel extensions : if there is already an official JWT extension for your domain model, you can make it JWT labelized by implementing a two-way transformation to an existing official or labelized metamodel extension along with its transformation documentation and test kit, make it approved by project leads and list it in JWT Metamodel Extensions/Labelized
  • extensions can obviously still be developed by anyone without being official or labelized, though their users can't be sure they'll be able to freely benefit from other parts of the JWT ecosystem, because of possible domain model specific incompatibility.

Metamodel evolution

In order to become better and answer more user requirements, the JWT metamodel evolves. In order to avoid conflicts and compatibility problems, it does so in a governed manner, and with the help of tools such as an automated version converter.

Metamodel Roadmap

  • initial metamodel : JWT up to 0.5 . This was originally AgilPro's metamodel.
  • aspect extensions : JWT 0.6 . Includes core metamodel improvements and the new aspect extension mechanism.
  • externalized metamodel : JWT 0.7 The metamodel will be in its own plugin.
  • small improvements are expected for the next version.

About JWT up to 0.5 and AgilPro metamodel

As said in the Roadmap, the metamodel has since changed so the following is not up to date, but still mostly valid.

Design

This document File:AgilPro MetamodelDescription.pdf describes the metamodel of AgilPro as it was of 2007-02-21. This document has been the basis for discussions on all working groups who have requirements on the meta-model.

Metamodel comparisons

JWT Metamodel and XPDL 1.0

The document File:AgilPro Metamodel.pdf describes an initial revision of the document comparing the JWT 0.5/AgilPro metamodel with the XPDL 1.0 schema. It covers all the XPDL elements as well as the Bonita engine vendor specific extensions.

JWT 0.5 Metamodel and BPMN

The document File:Comparison JWT BPMN v0 3.pdf describes the differences between the JWT 0.5 Metamodel on the one hand and BPMN on the other.

JWT 0.5 Metamodel and various others

A comparison with other meta-models (including BPM Guide's Simple BPM, BPDM, AgilPro, UML Activity Diagram, Event-driven Process Chains, List/Korherr's metamodel) as a result of an evaluation can be found in the following document: File:EvaluationExistingMetamodels.pdf.

Extending the JWT Metamodel

Extending the JWT Metamodel is necessary as soon as you need to enrich your model with custom information, for example information that is specific to your business or to your runtime execution platform.

JWT's Metamodel is based on EMF, for which there are several ways to add custom information, that are analyzed at JWT_Metamodel_Extension#EMF_model_extension_alternatives . Two ways are available out of the box in JWT :

  • 1. "classical" EMF extension : extend an existing type of the model with your own type. This is only interesting to create well identified subtypes, i.e. that could have been provided in the base model beforehand. If it is the case, please consider contributing it to JWT's core metamodel.
  • 2. EMF Aspects extension : manage instances of your own types in another model that let them refer to the main model's elements. This non-intrusive solution works with any model without prerequisite and allows to share type extensions between model types. In JWT, Aspects do this in a simple, typed way that allows for having custom-information coming from different third-party providers, while the genmodel file is a more complex example.

1. "classical" EMF extension

  • 1. define the EMF model
  • 2. To enable EMF child extenders, extensibleProviderFactory="true" has to be set on the genModel package of the EMF class you want to extend, and on your side you have to set childCreationExtenders="true" on the genModel package of your extending EMF class. See an example in jwt-we-plugins/jwt-we-sample-aspectchildextenders and Ed Merks' blog at http://ed-merks.blogspot.com/2008/01/creating-children-you-didnt-know.html
  • 3. create a new FactoryRegistry and override the Palette (or create new Palette)
  • 4. in Palette just add new model item ex. activityGroup.add(createCreationToolEntry(ModelPackage.Literals.TRANSPORT_OBJECT))

(courtesy of Kim Nguyen and a lot of others)

2. JWT Metamodel EMF Aspects Extension

Using JWT Metamodel Aspects Extension

JWT_Metamodel_Extension documents how to use store custom information in (workflow) models using Conf, Profiles and Aspects :

(for JWT developers only) Design and development of Aspects metamodel extension feature