Wednesday, April 9, 2008

Making MBean names first-class

Time for yet another problem that have annoyed me: names of MBeans. First of all, I find the something:key=value-notation noisy and non-intuiative in comparison to the dot-notation normally used in Java. This is, however, something I have gotten used to and have accepted.

What I have not accepted is that the MBeans are mere java.lang.String, which, to use an understatement, is not good because it forces developers to keep track on naming conventions, etc.

So, how to solve this? Easy, let's make MBean names first-class. This way, IDEs will help developers by suggesting possible keys and values in MBean name. Also, refactoring tools can be used to rename key and values, etc. Great stuff, I say!

Using some annotation tricks and reflection, I've made it possible to annotate an MBean with a special kind of annotation, which makes it is possible to do:

final class MyBeanImpl implements MyBean {
  // Code goes here.

which means that the name of MyBean is something:key=value. My current implementation takes an annotated class and returns the distinguised name; continuing the the example above you whould do like this to get the name of MyMbeanImpl:

final String myName =
  new DistinguishedName(MyBeanImpl.class).name();

I'm sure my implementation of this needs to be improved, but the concept is implemented by this class (see test-case for documentation), and this is how the @something looks like (well not quite, the linked code has different name, keys, etc, but I'll think you get it anyway).

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