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Common: (c) 2007 Together Teamlösungen

Java Open Source J2EE Templates

EJOSA - Enterprise Java Open Source Architecture

EJOSA (Enterprise Java Open Source Architecture) is a project supporting the effective development of J2EE-based web applications. The project is a "starter kit" and "best practices kit" which can be used as a good starting point. It offers a solution how to overcome the complexity of J2EE application development by using the Open Source products Enhydra and JOnAS. So EJOSA can also mean Enhydra and JOnAS Application, because we use Enhydra and JOnAS as our main components. The target audience of our project are developers with basic knowledge of J2EE, Enhydra and JOnAS developers or developers interested in:

Reference Models
Product-Line Software Engineering
Architecture and Pattern-based Engineering
Component-based Software Engineering

The SourceForge project

The SourceForge project for EJOSA contains all the needed links for mailing lists, News, CVS access and Downloads.

EJOSA Template combines Model Driven Architecture (MDA) and the Sourcecode Centric Development (SCD) model. It allows you to integrate both models in one environment to get the best of both worlds. It is very important to integrate the modelling part of the components directly into the developer's compile, run and test cycle.

The EJOSA project uses a template model for developing a multi-tier architecture. EJOSA template provide a collection of Open Source components which are bundled together and already pre-configured, so there is no need to write all the components once more. It also defines an easy to understand structure to be followed by the development of J2EE applications. EJOSA does not use an IDE, wizards or assistants. This means the users need to understand the whole process before they can develop their own J2EE application. EJOSA can be used to make a prototype fast and easily without having to throw away the prototype result for continuing the project. So we keep EJOSA Template simple.

Picture: EJOSA Template Structure - click to enlarge

Picture: EJOSA Template Process - click to enlarge

Articles about EJOSA

Technology - What is EJOSA Template ?

EJOSA Template offers easy to use templates and is a good starting point for your J2EE development based on Enhydra and JOnAS application structure.
EJOSA Template provides a collection of Open Source components which are bundled together and already pre-configured, so there is no need to download all the components separately (see ejosa/ext-libs/readme-external-libs.txt for a list of included components). Just unpack the file and you have everything you need to start your J2EE development.
EJOSA Template defines an easy to understand structure to be followed by the development of J2EE applications.
EJOSA Template does not use an IDE, wizards or assistants. This means you need to understand the whole process before you can develop your own J2EE application. On the other hand you have the freedom to choose your own IDE.
EJOSA Template can be used to make a prototype fast and easily without having to throw the prototype result for continuing the project. This means projects use EJOSA Template can scale.
EJOSA Template combines Model Driven Architecture (MDA) and Sourcecode Centric Development (SCD) model. It allows you to integrate both models in one environment to get the best of both worlds. It is very important to integrate the modelling part of the components directly into the developer's compile, run and test cycle.

Picture: Aspects from the J2EE-Technology - used by the EJOSA-Template model

OMG best practices for MDA

Application of available Reference Models
Application of Product-Line Software Engineering which separate Domain Engineering and Application Engineering.
Application of Architecture and Pattern-based Techniques like using Common J2EE design patterns. EJOSA Template only uses some of the J2EE design patterns which are a must and does not try to use all of them. This keeps EJOSA Template simple.
Application of Component-based Software Engineering which consists of following techniques:
Object-oriented and Extended Object-oriented Programming delivered by general purpose programming languages like using annotations and metadata
Generative Programming like using templates and generators
Programming using Frameworks
Aspect-oriented Programming
Business Rules Programming
Experiences taken from development of OpenUSS and other applications

Use of EJOSA in different information systems

Picture: Typical use of EJOSA - as your technical infrastructure

EJOSA can be used to create transactional business applications (OpenUSS, mdaVOFI, etc.). For this purpose it uses AndroMDA general Model-Text/Code cartridges (transformation definitions) which are using following language elements e.g. <<Service>>, <<Entity>> and <<Identifier>>, for building J2EE transactional applications. This is the scope of EJOSA application variants.

Further you can build your own variants by defining your own application scope. An example for this purpose is the product family mdaVOFI which may consist many of VOFI variants (end products). These variants serve as the scope of mdaVOFI. In mdaVOFI you also have a VOFI language which is using following language elements e.g. <<VoofiVofi>>, <<VoofiPeriod>> and <<VoofiPayment>>. To be able to have an executable code you need to transform the VOFI language into a general transactional business application language based on the language elements described by AndroMDA (see above). To implement this, EJOSA uses Model-Model cartriges (transformation defiinitions) which is based on MTL and/or ATL.

Persons

Lofi Dewanto
University of Muenster
Assistant researcher at the Institute of Business Informatics and Controlling
Chairmans - Prof. Dr. Heinz Lothar Grob

His experience in programming began 20 years ago with Basic for IBM Compatible PC/XT. After he finished his study at Business Informatics Faculty at the University of Muenster, he is working as assistant researcher at the Intitute of Prof. Dr. H. L. Grob. In his spare time he writes articles for German "Java Magazin", "Der Entwickler" and "Linux Enterprise".
http://members.tripod.com/~dewanto

Torsten Menzel
Leipzig University of Applied Sciences
Free staff at the Institute of Information Systems and Multimedia Technology
Chairman - Prof. Dr. K. Hänßgen

Torsten Menzel is working at the Leipzig University of Applied Sciences together with Prof. Dr. K. Hänßgen from the Institute of Information Systems and Multimedia Technology. His research interest concentrates on internet technologies, e.g. Java, XML, web graphics and open source databases. Torsten is developer and designer of EJOSA and OpenUSS.

Arturo Morales and Ricardo Beltran
National University of Pedagogy in Mexico City.

Alfred Madl
CEO from Together Teamlösungen in Austria. He is also the software architect and project manager of Enhydra. He is the advisor and consultant for EJOSA.

All OpenUSS developers are also working for EJOSA!

EJOSA Development Roadmap

Developing the EJOSA Templates during the year 2002
Opening the Sourceforge website in December 2002
Creating PiggyBank example in December 2002
PiggyBank example is online since January 2003
A swing client is available for PiggyBank example since January 2003
A UML diagramm added to PiggyBank example since February 2003
EJOSA homepage is updated completely in March 2003
Adding MDA with AndroMDA (Model-Text transformation) during the year 2002 - 2004
Adding MDA with MTL (Model-Model tranformation) during the year 2004 - 2005 for a better product families scoping
More developments and integration of Open Source products in EJOSA are to come ! Discuss with us what you would like to see in EJOSA ! Or just open a feature request for this purpose.