24 February 2010

Editing Resource Bundles in Eclipse

Playing around with the Apache Roller blog engine, I noticed that some of the localized German text messages were missing or broken. Roller uses plain old Java resource bundles instead of the NLS mechanisms offered by Eclipse. Editing resource bundles for multiple languages in parallel is rather a pain with a plain text editor, so I was looking for an Eclipse plugin to do this job.

(Just to avoid any confusion, even though I've been writing a lot about OSGi bundles, the term bundle is only used in the sense of a resource bundle, or properties file, in this article.)

I found two solutions, both of which have minor bugs and lack some documentation but are very helpful nevertheless. And it turned out that the second solution uses code from the first one:
At first, I tried the Resource Bundle Editor. The latest version is from 2007, and some people have reported conflicts with newer Eclipse versions. I installed the Bundle in my Eclipse 3.5.1, and did not notice any version conflicts at all.

However, the Resource Bundle Editor does not parse the properties files correctly. It does not recognize exclamation marks as comment signs. For comment lines of the form
!some.key = some value
the editor will display a bogus key !some.key.

Looking at the sources, I found the the PropertiesParser class only recognizes a subset of the valid properties file syntax.

After that, I had a look at the Eclipse Babel editor. Unfortunately, the Babel project does not yet provide binary downloads, so you have to build the two plugins from source.

As it turned out, parts of the Babel sources are derived from the Resource Bundle Editor sources, and the same incomplete parser code is also used in the Eclipse project in class PropertiesDeserializer.

I changed a regular expression in the source to fix the "!"-problem. You can get the binary plugins including my patch from here:

After installing the plugins, go to Window | Preferences | Messages Editor and deselect the option Setup validation builder on Java projects automatically, or else you may get lots of error markers on other properties files which are not used as message bundles at all. I also set the Reports severities to Ignore and the Displayed Locales to de to narrow the Editor display to the language I'm actually working on.

To edit a resource bundle, select the properties file in the Package Explorer and open it with the Messages Editor via the context menu.

Here is a screenshot of the Messages Editor in action:

With the additional toolbar buttons, you can limit the view to missing or unused translations.

    3 comments:

    Pasi said...

    I couldn't get this working. I put the two jars into the plugins folder of Eclipse. Then I launched eclipse with the -clean argument. After that I couldn't find the Messages Editor in Window/Preferences.

    Harald Wellmann said...

    Which Eclipse version are you using?

    Marek said...

    I guess you should put files in dropins directory, not plugins.