How to filter ressources during build in Eclipse project?

Question

I have an application that uses several configuration files (let just consider appli.properties here). These files contain several values that depend on the environment. We can find some information such as:

server.port=${envi.server.port}

On other side, I have a set of properties files, one per environment (dev.properties, homolo.properties, etc.). They contain the values for some properties in configuration files. We can find here this kind of properties:

envi.server.port=4242

My build is handled by Maven2. Everything is working fine.

However, I now need to import my project into Eclipse. My main concern is about the configuration files filtering. Indeed, if I do not modify anything in my Eclipse parameter for my project (after a mvn eclipse:eclipse command), then all my configuration file will keep the property keys (i.e. ${envi.server.port}) instead of their values. And with such configuration files, my application will not run inside Eclipse...

So I tried two solutions:

• A full-Maven solution, using m2eclipse plugin. I add a Maven Builder in the project configuration, and then, each time a build is made, the filtering is done on the files.
• Ant (which is only used inside Eclipse). I've hardly defined a task that simulates the Maven2 filtering of files in Ant. This task is only dedicated to the filtering, no compilation.

The common problem of these two solutions is that the filtering is made at every operation (essentially saves on Java class edition), and then take time. The second solution is however quicker (3 seconds) than the first one (more than 10 seconds).

What do you think of my approach? How would you do that, in a better way?

Answer 1

If the resources are not changed that often, you can set the Maven build to only run after a Clean build, then it won't interfere so much, this doesn't do anything to speed up the build however.

As far as making the filtering quicker, I don't know of any other simple mechanism that will help, as you've said you need either Ant or Maven to run the filtering, and they both take some time to set up before building, resulting in the slow down.

If this is causing you a lot of problems, you can write a custom Incremental Eclipse builder that performs the filtering on the deltas. This should be considerably quicker, but obviously a lot more effort to write.