We've all been there, you start with a class and a simple constructor that makes total sense. As time goes by, you keep adding features and the list of constructor arguments grows … and grows … until … it becomes unusable. This is exactly what happened with the Cache class in Ehcache.

The version 1.0 constructor looked like this:

However, with version 1.7 this turned into:

There are a lot of downsides to relying on constructor parameters like this:

• the author of the class needs to continue to overload the constructors to add new parameters
• users need to decide which overloaded constructor they want to use
• users need to figure out what sensible default values are for the values that they're not interested in
• it's very easy to accidentally put a value at the wrong place and provide wrong parameters
• reading the constructor afterwards is a nightmare and can't be done without looking at the Javadocs at the same time, for instance:

However there some advantages:

• you can enforce which parameters are mandatory
• at instantiation you can validate the constructor parameters
• at instantiation you fully set up the instance without requiring users to call an initialization method

So, we decided to change the Cache constructor approach in Ehcache 2.0 and use a builder pattern with a fluent interface, keeping the advantages of the parameters approach but solving all the problems.

The version 2.0 constructor looks like this:

We then created a constructor in CacheConfigurator with the strict minimal number of parameters that are required for a cache to function:

All the other parameters are implemented as fluent interface methods as well as regular setters and getters so that instances of the class can be used as beans:

This allows the example above to be rewritten like this:

The end results are that:

• we can continue to expand the CacheConfiguration class without ever having to change the constructors of the Cache class
• the user doesn't have to figure out the defaults for parameters he doesn't care about
• the configuration parameters are self-explanatory by simply looking at the available API methods
• anyone can read the usage of any Cache constructor and understand what each configuration value's purpose is

Ever since I upgraded to Snow Leopard 10.6.1, my MacBook Pro startup and shutdown was much slower than before.

I searched for a quite a while on forums to find the solution, but nobody seemed to know a solution. I finally figured out what it was. It seems that somehow the ownership of my startup volume's root directory (/) wasn't assigned to the root account anymore, but to my account instead. This made the kernel prelinking fail since it requires that root is the owner.

This is how you solve this after launching the Terminal app:

You'll have to enter your password after the first command.

Hope this helps someone, since it was really frustrating to have these slower startup/shutdown times for me.

Terracotta 3.1GA was released a few days ago and sports some interesting new features that are specifically geared towards clustering Hibernate second level caches.

I decided to create a series of video tutorials and presentations about Terracotta's new clustered caching capabilities and will demonstrate most of this from our Examinator reference application.

The first video highlights how to install, setup and use Examinator as a basis for the next videos.

Enjoy!

I picked music back up after a loooong hiatus of 7 years. I decided to evolve together with the world and to broadcast myself .

Did the first one last night. The song is "All The Kings Horses" from Robert Plant and the Strange Sensation. When I heard it playing last afternoon from my iTunes collection, I couldn't help picking up my guitar to figure out the chords and such. This recording is the result of a couple of hours searching and rehearsing. I'm considering adding it to a concert repertoire I'm preparing, as one of the few cover songs.

Anyways, my YouTube channel is located at http://www.youtube.com/gbevin and I'll be posting new entries as I learn and compose songs.

Hope you enjoy it, and if you don't, still be nice

Hi everyone,

Calling all hands on deck here, we're participating in a music contest and they finally opened internet voting. If you can't see the 'vote' button it's because they tie individual votes to IP addresses and someone behind the same firewall has already voted.

Please vote for my band Flytecase at

Thanks a lot for your support,

Geert