Since I started working on the TextUML Toolkit more than a year ago, I have been asking myself whether it would make sense to make it available under an open source license.

Open sourcing a product is a tough decision. Once you take that road, there is no way back, at least not without risking a backlash from the community (of course, if you managed to build a community). And even though there are more and more examples of successful businesses built on top of open source offerings, they are still the exception. However, from day one, my plan for the Toolkit has always been to give it away for free. Going from “free-as-in-beer” to “free-as-in-speech” is not nearly as traumatic.

I resisted to the idea while I was working on releasing version 1.0, as I considered it as potentially distracting and of questionable value, as then I knew exactly what I wanted to ship and how to get it done. However, now that 1.0 is out of the way, it seems the right thing to do. The first release provided a good starting point, but the project certainly needs more hands on deck to get to the next level. It is also clear that an open source license means a lot when you are catering to a developer audience.

So, you heard it here first: the next release of the TextUML Toolkit will be licensed under the Eclipse Public License. The source code is already available on SourceForge, and user forums and issue tracking are now also hosted there.

Joining the Eclipse Modeling project (more specifically the MDT subproject) is an option for the future, depending on whether the project succeeds in attracting other contributors.

Using the tool, spreading the word, asking and answering questions on the forum, reporting problems and requesting features are all great ways of helping. Regarding new features, the project needs help on two main fronts: broader coverage of UML (state machines, activities), and better IDE features (such as content assist, templates, symbolic search and refactoring). If you like the textual notation approach, the tool, and feel like you could lend a hand, please do, the TextUML Toolkit needs you!

I just completed the code for supporting parameter direction modifiers. When this feature makes into the next build, modelers will be able to choose for named parameters any of the standard parameter direction kinds: out, inout, or (the default) in. By the way, the syntax for specifying return types remains the same. Here is an example:

  operation op1(in p1 : String, out p2 : String);

Java developers might consider this feature unnecessary as there is only one way of passing parameters in Java, but for distributed applications (such as those using CORBA or web services) these modifiers are quite relevant.

The corresponding support for rendering operation parameter direction kind modifiers has been added to the TextUML model viewer (decompiler) and EclipseGraphviz graphical rendering component.

This is the first new feature since version 1.0 was released.  The impact of implementing it was quite minimal to the code base, so I am looking forward to implementing the next notation feature. The question is: what feature? Any suggestions?

One potential downside people often point out about using TextUML as a notation for UML is that it is yet another language to learn. But that is not really a well founded argument. TextUML is not a full-blown language, it is just an alternative notation for UML, the de facto standard language for modeling. The language semantics of UML are defined in terms of an abstract syntax, and even though the specification includes sections about the graphical notation, it clearly supports the idea of alternate concrete syntaxes.

Moreover, we really shouldn’t care much about the actual notation being used, be it the standard graphical notation, TextUML or any other textual notation. I surely don’t. Regardless what notation you use for creating UML models, in the end there is only one language. All you know about the semantics of UML model elements is still true no matter what syntax you choose (for instance, if you know your UML, you should easily become productive with the TextUML Toolkit by just glancing over the notation guide now and then). In fact, I predict a time where people will want to move between different notations across tasks and time. Also, in the same team, different people will be collaboratively creating UML models using different notations.

This will only be possible because supporting a new concrete syntax is much simpler than supporting a whole new language (by the way, that is the same reason why I believe UML-based DSLs to be a better option than homegrown proprietary DSLs, but I digress). Any reasonably good programmer armed with a parser generator and knowledge of the metamodel should be able to write a compiler for a textual notation for UML, and Eclipse makes it really easy to provide basic IDE features such as those you see in the TextUML Toolkit. Also, there are tools in the horizon such as IMP and TMF that will make these tasks really a breeze.

Meanwhile, you can stick with what is here today.