keyboardsamurais.de thoughts on software development, warts and all…

Google Gears, the app that would’ve been a godsent – ten years ago

In case anyone accuses me of not getting the idea of Google Gears, let me say this: I don't get the whole Idea of google gears. I mean come on, it caches your javasript and html for offline use in a fashionable way and enables you to enter some input to your app which is later synchronized when you reconnect to the web. All right, this will certainly make things like playing ajax Tetris a whole lot easier. The weblogs are abuzz about how google gears is better than the second coming.

But wait...do you spot the error? Wasn't Ajax meant to do some significant computing on the server side? Wasn't the whole promise of Ajax, that you'd get some meaningful data from a remote server in a quick, painless way?

Right. What Gears accomplishes is nothing like that (how could they, it's technically impossible). Of course, you would be able to edit your spreadsheets and word processors but these have been around for offline use since the advent of personal computing. In other words: Google Gears will make it easier for developers that feel comfortable in that niche that is Ajax desktop computing.

But they do this in a way that is downright scary. Instead of keeping it simple, they add this enormous complex layer of technology between your browser and the actual server. God knows how any sane developer is going to be able to debug the mess this will likely create in all those bug scenarios. Additionally, webapp developers need to comply with some design principles of Gears to make their apps "Gears ready".

To make a long rant short: I know there are a lot of people out there, who desperately wish for a network computer - and so they hack away on applications that use ajax locally and eventually they can synchronize their data to the server. It's a nice toy for a computer hacker, but I think by the time something as complex as this will be usable by Mom and Dad, ubiquitous WLAN will be a reality and the need to use these frameworks will have disappeared. But let's wait and see if anyone can come up with some kind of killer app, that turns it all around ...I highly doubt it.

Pain is the cost of Spring MVC’s elegance

I'm surprised about how far Spring has come without ever adressing simple everyday problems. If you really, honestly want to use Spring for your application all the way through, be prepared for some good shockers. Want some spring oddities?

Spring MVC and the <welcome-file> directive

If you use Spring's awesome MVC framework you will likely encounter one problem that is common among Web frameworks. If the first page you want to open is a jsp page with a Controller - i.e. a page where some java code is executed to prepare data for the invoked jsp...there seems to be no traditional way to do it.

Say you want to be able to access the url http://server.com/ to your servlet container that's just a directory. It will list the direcoty (if listig is enabled) or just show you a blank page. That is, unless you have defined a <welcome-file> directive in your web.xml which looks for a particular file to load in this case. But this is exactly the problem.

Assume you have defined the following:

<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>

And the index.html is the formView of, let's say a SimpleFormController.

Now what your container will do upon a request to its root context is this. It will look for a file in your filesystem called index.html and try to deliver it. Of course your index.html is not really a file, it's just mapped by, for example, a SimpleUrlHandlerMapping. Game over for the Server. It will not deliver what you expect.

Unfortunately there is no universal way of telling the container to take a look into the Spring context for the url. There is not even a possibility in web.xml to do simple forwards to other urls for the <welcome-file/>.

Instead the solution that seemed most practical to me was, to create a jsp as the <welcome-file>, save it as index.jsp and insert the following code:

<jsp:forward page="index.html" />

I assume that you chose *.html as your url-pattern for the DispatcherServlet here.

Download sources of dependencies with maven

Maven is an amazing piece of software, despite all the criticism it has endured it is fascinating to me. However there is one short line that has made life so much easier for me:

mvn -Declipse.downloadSources=true

This tells maven to download all associated sources of jar files in the pom.xml. Amazing, how much easier it is to set up a project with proper debugging sources etc. There is even a cool eclipse integration available over at codehaus.org.

How to migrate from drupal to wordpress (and clean up all the nasty leftovers)

So, after three years of Drupal, I finally got rid of it. By the last version of Drupal (it was version 5.1) there was just too much stuff in there I didn’t need and lots of features missing that make up a first class blog management system or BMS (*omg* I so created a new word!!! – oh wait, someone came up with that already, whatever). I wanted to change to WordPress. Let me show you how I did it…

Eclipse WTP and Tomcat Tutorial

If you are not interested in all the technical details of Servlet development in eclipse and tomcat, and you just want a quick introduction on how to install an Eclipse based Web development environment with all the bells and whistles and create a quick Servlet, then this screencast is for you.

Actually i just wanted to play around with Wink, which is totally awesome. Maybe I will create a more sophisticated version of this tutorial later. Sorry for the messy audio and some content glitches, but I'm sure it will be helpful to some people anyways.