The MetaSieve Blog

January 8, 2010

Using Grails for creating UML diagrams

Filed under: Uncategorized — Tags: , — Björn Wilmsmann @ 7:59 pm

Back in the old days (like, 5 years ago …) when embarking upon a new software project you would (hopefully, that is …) usually start by sketching the underlying model using ER or UML diagrams.

No matter if you’re on the more enterprisey side of software development that requires more complex upfront documentation or if you’re going down the agile road, there had to be at least some sort of a model.

Problem is, once you’ve drawn that model in your favourite UML design tool or just with good ol’ pen & paper, you have to turn that model into code. Although the more expensive UML design tools allow for code creation and sometimes even feature round-trip abilities (that is code changes are reflected in the diagram), most of them are far from perfect in that they mostly produce fairly generic Java code that has to be heavily customised depending on the framework you’re using.

Even worse, if you use another language like Groovy or Ruby you likely have to start writing code from scratch.

However, fortunately for Grails there are two nifty plugins that offer an elegant way out (see for a Rails solution):

Both automatically create UML diagrams for your app’s domain model. The main difference between those two is that the former draws upon, a very promising web service that allows you to create UML diagrams with a Wiki-like syntax.

So, nowadays I don’t even bother firing up Visual Paradigm – the UML design tool I liked best before – anymore when I have to design a domain model. All I do is run ‘grails create-app’ and start writing actual domain class code! Thanks to GORM, Grails‘ object-relational mapping, writing actual code is easier and faster than drawing diagrams in a design tool.

Once I’m done I can use one of the plugins mentioned above to create a shiny UML diagram for impressing the customer and documenting the current state of the application.

Update: Sven Lange wrote a nice and more detailed blog post about Grails and UML diagrams, too:


January 4, 2010

Software Development on the iPhone? Almost there

Filed under: Uncategorized — Tags: — Björn Wilmsmann @ 10:36 pm

Last week I also touched on the subject of software development on mobile devices.

Well, it seems like we’re almost there. There is this video that sports a hacked iPhone which is operated with a Magic Mouse and a keyboard projected onto a table surface.

Combine that with the Mili Pro Video Projector and basically you’ve got everything you need to get started with writing code on the iPhone.

Sure, this is still not generally available and it’ll take some time until it is but I doubt Apple – being renowned for their revolutionary I/O devices – will miss this opportunity.

So, we can almost certainly expect an iPhone that incorporates these features in the not-so-distant future.

However, as both the iPhone doesn’t yet feature sufficient memory and CPU performance for a full-blown development environment and Apple most likely won’t admit any languages apart from Objective-C any time soon, we would have to find different ways to code on such an iPhone.

The most obvious solution in my opinion is a version control client app that directly commits changes to a Git or SVN server and displays the results in a browser window.

This is going to be very exciting and indeed could change the way we develop software.

January 2, 2010

Grails MagicNumbers Plugin 0.2.2 released

Filed under: Uncategorized — Tags: , — Björn Wilmsmann @ 5:14 pm

I’ve been busy today working on some improvements of the new MagicNumbers plugin.

The new version mainly features new methods for byte calculation, some additional time calculation methods and a bug fix with regards to displaying large numbers. Moreover, the plugin now also adds its methods to the Long class in addition to the Integer class.

Please have a look at the plugin documentation, too:

Grails MagicNumbers Plugin 0.1 released

Filed under: Uncategorized — Tags: , — Björn Wilmsmann @ 4:35 am

Inspired by RailsActiveSupport library, we’ve just released the MagicNumbers plugin that adds several time calculation methods to the Integer class:

With this plugin you now can do cool things like the following with Grails as well:


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