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Sunday, November 26, 2006

Generic typesafe DAOs with Hibernate and Spring AOP

I am currently working on a JEE-5 project using Spring and EJB3/Hibernate. When it comes to encapsulate the access to a database the DAO pattern is used. But it has some drawbacks:

If you want to write a typesafe DAO you must repeat yourself over and over again, writing almost the same DAO code for each and every business object. Of course, you can make the DAO a generic one, but then you are loosing type safety. But there is a better way since JDK5 introduces generics.

At the W-JAX in Munich Adam Bien talked about a very good article on IBMs developer site called "Don't repeat the DAO". If you want to implement a generic and typesafe DAO using Spring and Hibernate you have to check it out at:

Another good example using plain Hibernate/EJB3 can be found on the Hibernate page under

Sunday, November 19, 2006

Using Maven Embedder and logging almost drove me nuts

I was recently experimenting with the maven embedder component (Version 2.0.4) to embed Maven into IDEA using the embedder API.

Somehow I called the setLogger(...) method AFTER I called maven.start(). This almost drove me crazy, because I didn't get any output. The trick is, to call the setLogger(...) method before a call to maven.start(), e.g. just like this (as described in the maven docs, see

MavenEmbedder maven = new MavenEmbedder();
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
maven.setClassLoader( classLoader );
maven.setLogger( new MavenEmbedderConsoleLogger() );

It seems that it is currently (in Version 2.0.4) not possible to set the logger after the embedder was started.

Maybe this is helpful for others.

Tuesday, November 14, 2006

Tacx and the right contact pressure between tire and roller

Well, the summer season of cycling is over and I wanted to start practicing on my Tacx roller trainer again during the winter.

So I mounted my bike back on the trainer and started the virtual cycling. But comparing to my results of the last winter season something was totally wrong. My times were incredible slow and I had the feeling that I spent way too much power to drive as fast as the rides from last winter.

So I started digging the internet for the solution of my problem and found something interesting in a german cycling message board

The pressure between the tire and the roller was incorrect! Here is what you have to do to determine the correct pressure:

  1. Start Catalyst
  2. Slope=0
  3. Accelerate to 40 km/h ~ 25 mp/h
  4. Let it roll out
  5. After approx. 10 seconds the velocity should be 0 km/h. In that case the contact pressure is correct
  6. If the tire is still rolling after 10 seconds the contact pressure is too low
  7. If the tire stops earlier the contact pressure is too high

Monday, November 13, 2006

Attended W-JAX in Munich

I attended the W-JAX in Munich from 2006-11-06 until 2006-11-09. Lots of great speakers with some very good sessions about JSF, EJB3, Application Architecture Management, Agile Development and more.

Sunday, November 12, 2006

Release of IntelliJ IDEA Maven-2 Integration plugin 1.1

This version is a feature and bugfix release. Please checkout the release notes below and also the updated documentation on

Important note:

version 1.1 of the plugin, Maven was called via the start script
provided with the normal Maven installation. In order to get better
access to the running Maven process Maven now is called directly by
starting a Java process. This for example allows terminating the
running Maven process by the user.

Change notes:


  • Sorting of goals should not move Phases node from top position
  • Spaces in pathname of POM file causes build failure


New Feature
  • Add a "Cancel Build" button to the build output window
  • Add a "Close Output" button to build output window
  • Add a "Pause Output" button to build output window
  • Add a "Rerun Maven" button to build output window


  • Remove references to non-public Maven repository

Thursday, November 09, 2006

Release of IntelliJ IDEA Maven-2 Integration plugin 1.0.1

Version 1.0.1 is a bugfix release:
  • Removed reference to parent POM
  • Minor changes in build process with Maven
  • Java sources for corresponding XML schemas are generated during the build using the xmlbeans-maven-plugin
  • Updated documentation on
  • Added more screenshots