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Difference between revisions of "JWT Metamodel"

(Extending the JWT Metamodel)
 
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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.
  
 +
* 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.
  
== JWT metamodel comparisons ==
+
=== 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.
  
=== Comparison with other metamodels ===
+
Metamodel Roadmap
A comparison with other meta-models as a result of an evaluation can be found in the following document: [[Image:EvaluationExistingMetamodels.pdf]].
+
* 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 ==
  
=== Metamodel and XPDL 1.0 ===
+
As said in the Roadmap, the metamodel has since changed so the following is not up to date, but still mostly valid.
  
The document [[Image:AgilPro_Metamodel.pdf]] describes an initial revision of the document comparing the JWT/AgilPro metamodel with the XPDL 1.0 schema.
+
=== Design ===
It covers all the XPDL elements as well as the Bonita engine vendor specific extensions.
+
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.
  
=== Metamodel and BPMN ===
+
=== Metamodel comparisons ===
  
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.
+
==== 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 0.5 Metamodel and BPMN ====
 +
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.
  
== Requirements ==
+
==== 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: [[Image:EvaluationExistingMetamodels.pdf]].
  
=== Sources and contributors ===
+
== 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.
  
=== List of requirements ===
+
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 :
* BPMN2JWT transformation (SCOrWare project) : being able to store BPMN information that can't be mapped to JWT. This allows then to manipulate this information in JWT, but also to provide a perfectly bijective JWT2BPMN reverse transformation (notional "pivotal" metamodels)
+
* '''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.
* Bonita v4 XPDL "hook" support (Bull) : Hooks (as well as other Action-level features) should be stored in a Bonita specific metamodel extension. This extension should be typed so Bonita-specific UI extensions would know which metamodel extension they have to manage.
+
* '''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.  
* Service (WebService, SCA) call support (SCOrWare project) : requires to store and manage information pertaining to these specific Actions or Action extensions.
+
* Custom Action support (Bryan Hunt, MWE) : JWT users should be able to define custom Actions with custom metamodels, that might be exploited at runtime. Marc : I link this with the "black box Action" point of view, where Actions are merely linked blank "do something" slates that users implement at will.
+
* Imixs.org specific Action features support (Ralph Soika, Imixs.org) : imixs.org features depend on numerous Action-level properties that should be stored and accessible in JWT metamodel.
+
  
 +
=== 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)
  
== JWT metamodel extension ==
+
=== 2. JWT Metamodel EMF Aspects Extension ===
  
=== Goals of JWT metamodel extension (consolidated) ===
+
==== Using JWT Metamodel Aspects Extension ====
* allow JWT metamodel to be extended
+
[[JWT_Metamodel_Extension]] documents how to use store custom information in (workflow) models using Conf, Profiles and Aspects :
* 1. for JWT developers (ex. allow complex metadata, using static EMF for performances)
+
* prerequisites : [[JWT_Metamodel_Extension#Using_aspect_model_extensions|Using aspect model extensions]]
* 2. for users : as easily as possible (ex. without writing java code, using dynamic EMF or XSD for ease of use, using simple concepts ex. a property map)
+
* [[JWT_Metamodel_Extension#Creating_custom_aspect_model_extensions|Creating custom aspect model extensions]]
* in multiple orthgonal ways (ex. "typed" extensions), so different extensions with different aims and features can coexist, and each of them can be easily found and distinguished by their management code and business logic
+
** [[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
* 3. IN A SECOND TIME (more complex, several consequences, see further) provide ways to manage consistency of all typed extensions
+
** [[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]]
=== Design ===
+
* 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]]
  
=== Technologies ===
+
==== (for JWT developers only) Design and development of Aspects metamodel extension feature ====
Here is a list of available technologies to extend the JWT metamodel :
+
* Development : See bugzilla https://bugs.eclipse.org/bugs/show_bug.cgi?id=241567
* static EMF (loaded as instances of JET-generated classes). Requires to generate classes using a .genmodel file. Those classes must be available to JWT and specified in the workflow file.
+
* Design : [[JWT Metamodel Extension Specifications]] describes the initial specifications of the aspects metamodel extension mechanism :
* dynamic EMF (loaded as instances of DynamicEObjectImpl). Ecore schema must be specified in schemaLocation and available there.
+
** [[JWT Metamodel Extension Specifications/Requirements|Extension Requirements and Use Cases]]
* any XML following user-defined xsd schemas (loaded through XSDEcoreBuilder). XSD schema must be specified in schemaLocation and available there.
+
** [[JWT Metamodel Extension Specifications/Alternatives Study|Specification Alternatives Study]]
* any XML (without xsd schema), read by EMF (loaded as instances of AnyTypeImpl)
+
** [[JWT Metamodel Extension Specifications/Prototype|Metamodel Extension Prototype]] - working samples (added 20080527)
* any XML or other kind of text, read by EMF as string and parsed by custom XMLHandler or other custom parser
+
** [[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

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