More action with Struts 2
In a recent review of Struts 2 in Action, JW Blogger Oleg Mikheev notes that Struts 2 is "just a collection of extensions built upon WebWork, which is ultimately the right thing to learn before starting a Struts 2 project." While Struts 2 has some architectural flaws, Oleg calls WebWork well-designed, well-tested, and reliable. What are your experiences using Struts 2 and WebWork?

Also see "Hello World the WebWork way," a JavaWorld excerpt from WebWork in Action, by Patrick Lightbody and Jason Carreira.

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An AI tool for the real world

Knowledge modeling with Protégé

By Holger Knublauch, JavaWorld.com, 06/20/03

Knowledge about the application domain is one of the most important cornerstones of successful software projects. You must gather at least a basic understanding of the concepts relevant to your customers before you can begin coding. For example, you need to know how your customer's business processes work before you can develop a warehouse management system; you need to know that users who buy cat food might also be interested in cat litter before you can implement purchase recommendations for an online shop; and you need to know that a Quillflinger is a monster that flings quills before you develop a role-playing game.

We acquire such knowledge from domain experts and capture it in some kind of domain model. In simple cases, we can scribble these models on paper. This approach works fine for small projects and when the experts help us decipher their handwriting. But it's better to have models that directly translate into a Java program. For instance, we can use Unified Modeling Language (UML) to sketch the domain models with class diagrams and use cases. UML is quite good for quickly getting to an implementation, but it is basically a language for object-oriented programming that few domain experts fully understand. And it consists of a fixed set of modeling constructs (such as classes and attributes) that are not very useful when domain experts would rather talk about specific business processes, products, and monsters.

If you want to more closely involve your experts and customers in the development process, you need more than UML. In this article, you will learn how to use Protégé, a simple yet powerful tool optimized for building domain models. Although Protégé was originally developed 15 years ago to support knowledge acquisition for rather specialized medical expert systems, it has also become very popular for many other purposes. Protégé is open source and currently has more than 7,500 registered users.

In a nutshell, you can use Protégé for the following:

  • Class modeling. Protégé provides a graphical user interface (GUI) that models classes (domain concepts) and their attributes and relationships.
  • Instance editing. From these classes, Protégé automatically generates interactive forms that enable you or domain experts to enter valid instances.
  • Model processing. Protégé has a library of plug-ins that help you define semantics, ask queries, and define logical behavior.
  • Model exchange. The resulting models (classes and instances) can be loaded and saved in various formats, including XML, UML, and RDF (Resource Description Framework). Protégé also provides a very scalable database back end.


From a programmer's perspective, one of Protégé's most attractive features is that it provides an open source API to plug in your own Java components and access the domain models from your application. As a result, you can develop systems very rapidly: just start with the underlying domain model, let Protégé generate the basic user interface, and then gradually write widgets and plug-ins to customize look-and-feel and behavior. You can even give Protégé to your customers and, with little training, let them build their own knowledge and requirement models.

Discuss

Start a new discussion or jump into one of the threads below:

Subject Replies Last post
. Interesting ideas
By Anonymous 		1 07/19/08 02:56 AM
by Anonymous
. Populate the Protege KB without using the GUI
By Anonymous 		2 07/19/08 02:55 AM
by Anonymous
. Protege for software development
By Anonymous 		0 07/19/08 02:54 AM
by Anonymous
. please help~~~
By Anonymous 		0 07/19/08 02:54 AM
by Anonymous
. Development of Ontologies
By Emmanuel 		1 04/09/08 04:11 AM
by Anonymous


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