Friday 17 September 2010

Developing OSGi Applications with Apache Aries

Yesterday I blogged on how to get the free OSGi Applications tools from IBM Rational working on Eclipse 3.6 Classic. Having got the tools created the next step is to define a target platform. A target platform is the set of bundles you want to build and run your application with. Since Eclipse is a big OSGi application it already comes with a built in target platform for developing eclipse plugins. Since we are trying to create an enterprise OSGi application this isn't any good. We need a new one, but the tools don't come with one for free. In this post I will go through the steps involved in setting up a target platform for developing OSGi applications.

Before going on you'll need maven. You may have it already, but if not you can get it from the Apache Maven download page.
  1. The first step is to get a "runtime" from somewhere. The quickest way to get something quickly and easily is to build the Apache Aries Blog sample assembly. This can be downloaded from subversion here. Download it into an empty directory.
  2. In the empty directory run mvn. This will download all the bundles required to run the Apache Aries Blog sample. The bundles will be in the target subdirectory.
  3. In eclipse you need to open the preferences pane and navigate to Plug-in Development > Target Platform. Click the Add button.
  4. This opens a wizard with 4 radio buttons. You want to start with the first option titled Nothing.

  5. The next page is the target platform configuration panels. The first step is to choose a name. I have gone with Apache Aries.

  6. Right now the target platform has no bundles, so we need to add the directory of bundles we got from step 2. Click the Add button. A wizard will appear with 4 options, select the Directory option and click next. Then browse to the target directory generated in step 2.
  7. We now have bundles we can build against, but this isn't going to help run any tests. Some of the Apache Aries bundles depend on javax.transaction. The problem is javax.transaction exists in the JVM, but only contains a few exceptions from the package which causes bundles wanting to use javax.transaction problems. to fix that we need to configure the target platform. This is fixed by going to the Arguments tab and adding the following as a vm argument:

    -Dorg.osgi.framework.system.packages.extra= javax.transaction;version=1.1.0,  javax.transaction.xa;version=1.1.0  -Xbootclasspath/p: ${target_home}/geronimo-jta_1.1_spec-1.1.1.jar

    This does two things. The first is it tells the OSGi framework to export the JTA packages at version 1.1, which is the version expected by Apache Aries, and the second thing it does is add the extra classes onto the JVM boot classpath.
    Note: I added some spaces into the example to ensure it wraps on the blog. The only space that should exist when copied into the dialog is the one before -Xbootclasspath.

  8. Now you are done and can click the Finish button. The last thing to do is to make the new Target Platform the active platform. You can do this by checking the checkbox next to the platform you just created.

    Note: If you add or remove a bundle from the platform directory you will want to come back and hit the reload button to get Eclipse to notice.
Now you are ready to start developing your bundles, and when you want to test your application you can use the OSGi Framework Run configuration in eclipse. If you want to add more bundles to the runtime just drop them into the directory from step 2 and then reload the platform.

I'll blog another time about using the tooling to create a simple application.


David Bosschaert said...

Nice blog Alasdair. Great that you include the screenshots!

Alasdair Nottingham said...

No problem, always happy to help.

Ishu Sathya said...

Thanks for the lovely blog!!!Keep posting

PHP Training in Chennai
DOT NET Training in Chennai
Big Data Training in Chennai
Hadoop Training in Chennai
Android Training in Chennai
Selenium Training in Chennai
Digital Marketing Course in Chennai
JAVA Training in Chennai
Java training institute in chennai

saran said...

Good post. I learn something new and challenging on sites I stumbleupon on a daily basis. It's always interesting to read content from other writers and practice a little something from their web sites.
Digital Marketing Training Course in Chennai | Digital Marketing Training Course in Anna Nagar | Digital Marketing Training Course in OMR | Digital Marketing Training Course in Porur | Digital Marketing Training Course in Tambaram | Digital Marketing Training Course in Velachery

praveen said...

Its a wonderful post and very helpful, thanks for all this information. You are including better information regarding this topic in an effective way. T hank you so much.

Dot Net Training in Chennai | Dot Net Training in anna nagar | Dot Net Training in omr | Dot Net Training in porur | Dot Net Training in tambaram | Dot Net Training in velachery

Revathi said...

Here is the colleges details to study in Bangalore. You can select the best college details from the below mentioned courses that you love to study.thanks lot!!

android training in chennai

android online training in chennai

android training in bangalore

android training in hyderabad

android Training in coimbatore

android training

android online training

Mrbk30 said...

Very Informative blog thank you for sharing. Keep sharing.

Best software training institute in Chennai. Make your career development the best by learning software courses.

power bi certification in chennai
rpa training in chennai
uipath training in chennai

Block said...
This comment has been removed by the author.