Wednesday, February 27, 2008

Qype video

Qype [kwaip] has posteda nice video that explains how its name is pronounced. German only. It is supposed to be shown in German cinemas soon. Will be interesting to see it there and to see how people react.

Tuesday, February 26, 2008

RHQ SVN running at full speed

When we first announced RHQ, we put the state of our internal svn repository at RHQ, but did not start right away committing new stuff into it.
Last night we switched over to the RHQ svn and added all the stuff that was developed since the first cut over.
So expect lots of changes going into it from now on.
If you don't want to check out the source, but just browse around, you can use the source viewer at

Don't forget to checkout the documentation in the forums.

You can also meet developers on #rhq at

Tuesday, February 19, 2008

Be careful with @OneToOne and lazy loading

When modelling an entity one sometimes wants to have information in a separate table even if it would exist only one time for a given entity. Think of a 1:0...1 composition. This could be handled as embedded in the primary entity, but perhaps you don't want to do this as the dependent object is huge and you don't always need it. The dependent table could even live in a different table space for that reason. Or just for relational normalization reasons.

For the @xxxToOne relations, JPA 1.0 spec sees Eager loading as default. One can give a *hint* that the dependend end should be lazily loaded, but this is only a hint.

Now when you have an optional @OneToOne relation, Hibernate (at least) needs to do an additional select for that relation to find out if the dependend object is null or not. For a mandatory (1..1) relation it can just install a proxy to lazily load the relation, but this is not possible for 1...0..1.
See e.g. for an explanation.

Thursday, February 14, 2008

Project RHQ is here

At JBossWorld in Orlando, Red Hat anounced together with Hyperic the new Project RHQ. Why do I write about it?
Lets quote from the press release:
It is anticipated that the RHQ project will serve as the code base for JBoss Operations Network v2.0 (JON 2.0), due out in the Spring of 2008.

Well, I was for over a year working on JON 2.0 and will continue to do so. So this is a big step for me and the others of our team.

The two press releases:
Hyperic press release
Red Hat press release

Code is available at and anonymous svn access has been set up as well.

Be sure to check out and start contributing today :-)

Friday, February 01, 2008

Add mod_jk to the Apache that comes with Tiger

Mac OS X Tiger (and Leopard, perhaps also earlier versions) come with an Apache httpd installed.
If you want to use this as frontend for a Tomcat or JBoss with embedded tomcat, you need to install mod_jk.

The canonical way is to use the macports port. Unfortunately will this a) try to install apache2 and b) fail building (at least for me).

Fortunately there is a blog entry out there that explains how to do it by hand.

Note, that the link to the apache download is outdated. The best is to go to the root of the dowloads and just download the latet version.
When you are using mo_jk in front of a embedded tomcat in JBossAS, you also don't need the workers.tomcat_home directive in the config file.

Ah, and when this works, don't forget to trim down the loglevel in httpd.conf from trace to info. Else you will end up with gigabytes of logs.

JkLogLevel info