A review of OSGi DevCon 2009, delivered at the first meeting of the UK OSGi Users' Forum.

1. OSGi DevCon 2009
Review
Neil Bartlett - UK OSGi Users’ Forum

2. Themes
OSGi Ubiquity OSGi for Eclipse
Developers
Enterprise OSGi
“Symmetric” service
Distributed OSGi oriented programming
Tooling JSR 294, Jigsaw, IBM/
Sun Rumours
API Modernisation

3. Ubiquity

4. Ubiquity
My third EclipseCon/OSGi DevCon
2007: Some people know what OSGi is.
2008: Most people know what OSGi is,
some have developed for it.
2009: Many people know and have
developed for OSGi.

5. Services and Apps
OSGi for modularity is mostly a done
deal. All* app-servers & ESBs using it.
Next wave: Services/Dynamics, and
OSGi for Apps.

6. Enterprise

7. Goals
Adapt enterprise tech without creating
“editions”.
Preserve compatibility for users of
enterprise APIs.

8. Timeline
Updated (R4.2) core & compendium
specs in June 09.
Most changes are already implemented
(provisionally) in Equinox.
“Enterprise Profile” in December 09.

9. Parts
Blueprint
Distributed OSGi (RFC 119)
Java EE Modularity

10. Blueprint
Essentially Spring-DM...
But name “Spring” is a trademark.
“Enterprise Programming Model”.

11. Old Spring
Customer
Manager
Customer
DAO
DataSource Log

12. Spring-DM/Blueprint

13. Services as the Glue

14. Interoperable!

15. Java EE Modularity
For OSGi devs: add QoS (e.g.
transactions, declarative security) to
OSGi programming model.
For EE devs: enable OSGi modularity
without breaking existing APIs.
Deployment of standard EE artefacts
(WARs and EARs).

16. Distribution

17. What Is It?
Normal OSGi is intra-JVM only.
D-OSGi makes the services
programming model distributed.
Transparently publish services outside
the JVM.
Transparently bind to services from
other JVMs (or other non-Java runtimes).

18. Timeline
Spec will be included in R4.2 in June.
Reference implementation: Apache CXF
available now.
Eclipse Comms Framework (ECF) also
implements.

19. Distribution
Just add a property to the published
service: osgi.remote.interfaces=*
Extender bundle will automatically
make the service callable remotely.
Protocol depends on extender impl. E.g.
SOAP, R-OSGi, XMPP, Skype...

20. Distribution
Find a remote service somehow*.
Extender bundle will create a local proxy
service for it.

21. Discovery
Publishing and look-up of services.
Many ways to do it, many challenges.
Examples: SLP (RFC 2608), Bonjour/
Zeroconf/DNS-SD.

22. Controversy?

23. Controversy?

24. Key Points...
D-OSGi allows transparent treatment of
remote services
But it also allows clients to filter remote
services and know when a service a
remote proxy.
Is this enough...?

25. Key Points...
No new protocols!
D-OSGi wraps existing protocols.
It is optional.
Fears of bloating the core spec seem
misplaced.

26. Tools

27. Tools
Lots of tooling discussions.
One evening BoF, a Summit, many
hallway conversations.
More details from David.

28. API Modernisation

29. OSGi APIs “Feel” Old!

30. Ideas
Generics Replace arrays with
collections
Don’t return null
arrays Replace int masks
with enums
Replace Dictionary
with Map Expanded filter ops
Services returning JSR 294 support
multiple instances

31. More Radical Ideas
Should exports have ranges rather than
imports?
Make all events (ServiceEvent,
BundleEvent etc) asynchronous.

32. OSGi for Eclipse Devs

33. OSGi for Eclipse Devs
Most Eclipse developers now know they
are using OSGi!
Some even experimenting with Services
(instead of Extensions).

34. Declarative Services
Eclipse SDK Galileo includes SCR.
Riena aids integration of Services and
Extensions.
Component models tutorial (DS,
Spring-DM, iPOJO) was packed.

35. “Symmetric” Services

36. What Is it?
Giving some power back to service
producers.
Producers have no idea if anybody even
needs the service they offer.

37. Why?
“On-demand” services.
Filtering on behalf of a consumer.
Service proxies – prevent the underlying
service from being seen.
Needed for D-OSGi but will be part of
core spec.

38. How It Works
ListenerHook – discover who is listening
for which services.
EventHook – filter service events before
they reach listeners.
FindHook – filter results of
getServiceReferences() calls.

39. How It Works
Hooks are themselves published as
services.
Powerful but NOT for the faint-hearted.
Wait for frameworks to make this easier?

40. Rumours...

41. JSR 277 Is Dead

42. Jigsaw Is Undead

43. Jigsaw

44. Jigsaw
Alternative module system to OSGi.
NOT a standard, just a Sun project.
EVIL.
Cannot be killed by silver bullets, but a
Big Blue bullet might work...

45. JSR 294
Not necessarily evil...
Java language support for modules.
Designed for Jigsaw, but may help OSGi
also.