Comments on: OSGi Declarative Services, Eclipse Galileo Feature #2

By: webdesigner

webdesigner — Sat, 28 May 2011 12:49:41 +0000

thanks for the useful info

By: Norm Heske

Norm Heske — Fri, 31 Jul 2009 12:44:33 +0000

Chris,

I submitted Bug 285272.

Norm

By: Chris Aniszczyk

Chris Aniszczyk — Thu, 23 Jul 2009 21:54:43 +0000

Norm, it’s a bit complicated as your bundle doesn’t need to have any direct dependencies on DS.

In most cases, you shouldn’t have a dependency to DS via an Import-Package or Require-Bundle. In the new version of DS that shipped with Eclipse 3.5, you can use POJOs with DS.

However, I think we could do some extra validation in PDE when you validate a launch configuration and we come across a bundle that uses DS but DS isn’t in the list of bundles we launch against. Could you open a bug for this?

By: Norm Heske

Norm Heske — Thu, 23 Jul 2009 03:44:25 +0000

Thanks Chris. Should the example template add that as a required bundle or have a comment to that effect? I suspect others will also have trouble running the example.

By: Chris Aniszczyk

Chris Aniszczyk — Wed, 22 Jul 2009 16:11:41 +0000

That’s correct Norm.

You have to make sure that the DS bundle is added to your launch configuration and started (the default is for the bundle to be automatically started, but you have to add it to the launch configuration first).

By: Norm Heske

Norm Heske — Tue, 21 Jul 2009 23:58:18 +0000

Not sure if I was doing something non-standard, but I was having a hard time getting the OSGi Declarative Services Example provided in Galileo to run. Eventually, I explicitly added the org.eclipse.equinox.ds bundle and its associated dependent bundles and it worked. Seems to me that ds bundle is not flagged as required and the xml files are ignored.

By: Víctor

Víctor — Tue, 07 Jul 2009 10:09:31 +0000

Thanks for the Hint, Chris!

By: Chris Aniszczyk

Chris Aniszczyk — Tue, 30 Jun 2009 12:35:11 +0000

Hi Victor. As of Eclipse, it’s possible to use DS in a lazy fashion due to the specification updates in OSGi r4.2

PDE provides the latest tooling for DS files in Eclipse 3.5 and Equinox provides the latest DS runtime.

Just remember that your component files need to be in the new DS 1.1 namespace…
http://www.osgi.org/xmlns/scr/v1.1.0

Also, ensure that the bundles are lazy started…
Bundle-ActivationPolicy: lazy

That should be it! Good luck!

By: Víctor

Víctor — Tue, 30 Jun 2009 09:03:16 +0000

Hi Ian,

nice articles regarding our beloved Galileo release train. Even for a day by day user, Eclipse keeps surprising with new cool features!

Correct me if wrong, but I’ve used DS in Ganymede, and found a rather odd issue regarding Service contribution: these will only be contributed if the bundle is activated. Otherwise, they are not. I found that it killed the real power behind DS. I had t create my own support bundle that activated those bundles defining declarative services.

I believe the PDE team was working to change this for 3.5, based on the latest OSGi spec update. Is DS lazy loading already supported in 3.5?

Cheers,
Víctor.

By: Kamil Demecki

Kamil Demecki — Wed, 24 Jun 2009 21:34:10 +0000

Declarative services is cool solution. I emphasize “declarative” word to express way of divide logic. But why using XML to define this spliting logic ?

Dividing is fine, one code is responsible for services and other how these services inter-operate (like in Guice). Also Ejb3 come out from XML to Java and annotations.

From I know, one strong point of XML is easy GUI wizards which operate on this XML, but one consistent solution in Java take advantage, specially speed of refactoring.

Eclipse is cool, speed of searching dependencies in plugin.xml is ok in middle-size project, but why not Java Module to express this declarative logic ?