1. GlassFish OSGi - A Modular Runtime for Hybrid Applications
Peter Doschkinow
Senior Java Architect

2. The following is intended to outline our general product direction
The following is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, and timing of any features or functionality described for Oracle’s products remains at the sole discretion of Oracle. 2

3. Agenda
OSGi basics
OSGi meets Java EE
Hybrid applications
GlassFish v3 architecture
GlassFish and OSGi
Demos

4. What is OSGi
Set of specifications delivered by the OSGi Alliance
Originally for embedded devices, set top boxes, network
Service oriented dynamic module system for Java
Breaks applications into modules(“bundles”)
Bundles can be managed dynamically without restarting the container
Multiple versions are supported
Dependencies explicitly defined with clear boundaries

5. Execution Environment
OSGi Layers
Service
publish/find/bind intra-VM model
Life Cycle
bundle lifecycle in OBR
Module
consistent class loading rules
Execution Environment
CDC, Java SE
Security

6. Module Layer
Bundle – a unit of modularity in OSGi
Encapsulation
Lifecycle independent of the JVM
Versionable
Packaged as a JAR
classes + Manifest with OSGi metadata
Very explicit dependency specification
Well defined dependency resolution rules

7. OSGi Metadata
Bundle-SymbolicName: com.acme.hello.startup
Bundle-Name: Hello World OSGi Sample
Bundle-Version: 1.0.1
Bundle-ManifestVersion: 2
Bundle-Activator: com.acme.hello.startup.MyActivator
Export-Package: com.acme.hello.startup;version=1.0.0
Import-Package: org.osgi.framework;version=1.3

8. Lifecycle Layer
Provides API to manage bundles
BundleActivator
BundleListener
Listens to BundleEvents

9. Service Layer
In-VM SOA
Service Registry
Register
Unregister
Service is a POJO
Service Dynamism
Service tracking
Service Discovery
LDAP filter based queries

10. OSGi Advantages Summary
Solves most problems that result from the insufficient Java support for modularity and dynamism
Defines a module system
Explicit code sharing through import/export of packages
Supports versioning and evolution
Lifecycle management
Dynamic deployment and configuration
Ease of deployment and management
Automatic management of code dependencies
Enforces sophisticated consistency rules for class loading
Bundle deployment order is not relevant

11. Java EE Platform of choice for enterprise applications
Widely used infrastructure APIs
JPA, JTA, JAXB, JNDI, JAX-WS, JAX-RS, JCA
Component Models (Servlet, EJB, JAX-RS)
Frameworks (JSF, CDI)
Ease of Use
Annotations, Convention over Configuration
Tools (IDE, Management, Monitoring)
Ubiquitous deployment platform for enterprise applications

12. Hybrid Applications use advantages from both worlds
OSGi + Java EE = Hybrid application
Hybrid application
An OSGi bundle
And a Java EE Archive
Leverage the capabilities of both the platforms
Enterprise applications can
be built as modular OSGi bundles
use OBR, Config Admin, service tracking, etc.
OSGi bundles can use Java EE services like JTA, JPA
Require a runtime that supports both standards
Current State
• OSGi Enterprise Expert Group (EEG)
– Relased OSGi Service Platform Enterprise Specification 4.2
in 2010
• Open source efforts
– Project GlassFish
– Project Aries
– Eclipse Gemini

13. OSGi Enterprise Specifications
OSGi Declarative Services
Declarative model to simplify the work with OSGi services
OSGi Blueprint Container
IoC and DI framework, derived from Spring DM project
OSGi/JPA
OSGi/JDBC
OSGi/JTA
OSGi/JNDI
OSGi/HTTP Service
OSGi/Web Application
Web Application Bundles (WAB)

14. OSGi Enterprise Specifications
OSGi/JPA
Makes Persistence Units/Provider availabe in OSGi
Enhancement of JPA entities at runtime
Same packaging rules as JPA and also deploy entities as a bundle
Shared Persistence Unit and thereby shared second level cache
OSGi/JDBC
JDBC driver as DataSourceFactory
Dynamic discovery of driver details
Multiple versions of same driver
OSGi/JTA
JTA artifacts available as OSGi Services

15. Web Application Bundle (WAB) OSGi/Web Application
WAR + OSGi bundle configuration
Manifest-Version: 1.0
Import-Package: javax.servlet.http; javax.persistence
Bundle-ClassPath: WEB-INF/classes/,WEB-INF/lib/entities.jar
Bundle-Version: 1.0
Bundle-ManifestVersion: 2
Web-ContextPath: /hello
Bundle-SymbolicName: test.hellowab
Lifecycle now can be driven by OSGi
Wrapped WAR Support
webbundle:file:///myWebApp.war?Web- ContextPath=/hello

16. Strong community and developer adoption
Project Glassfish
Java EE RI
Java EE 5.0, Java EE 6.0
Open Source
Strong community and developer adoption
Sources, bug DBs, discussions at Java.Net
Roadmaps, Architecture Documents
Production Quality
GlassFish 3.1 – currently developed
Clustering, HA, centralized administration
Technology refresh, better OSGi support
Moving beyond GlassFish v2, work has already begun on GlassFish V3. The GlassFish community is acting in a very transparent manner. Public roadmap and requirements document (with community input). Roadmap, dates and features are subject to change.
At the core of GlassFish V3 is a microkernel architecture. Only the necessary modules are loaded during runtime (with no pre-configuration required). The application server core starts in less that one second and consumes a minimal amount of memory. As applications are deployed, only the required modules are loaded. If a web application is deployed, only the web container is started. If a Jruby application is deployed, then the Jruby container is started.
Improved enterprise feature:
Security: Role-based access control in management console
Scale management: Manage over 100 instances from a single console
Improved application versioning
- Rollback to prior version of an application.
- Goal (no commit): Multiple versions of an app running simultaneously.
Improved developer support:
Added features will not compromise ease-of-use
Dynamic language support (JRuby, Groovy, Jython, others)
GlassFish V3 is the delivery vehicle for Java EE 6 and its support of profiles.
Work has just begun and progress can be followed at

17. GlassFish v3 Architecture
Hundred
Kilobyte
Kernel

18. GlassFish v3 Modularization and Extensibility
Based on OSGi
Extensible
Extensive APIs to replace or extend features
OSGi also provides extensions capabilities
SOA based architecture
Services implement different types of interfaces
Java SE style with a META-INF/services file
HK2
OSGi style
Lazy loading based on usage patterns
Makes it easier to provide support for new container types

19. GlassFish v3 Runtime GlassFish v3 HK2 Module System Felix, Equinox
binding
static
binding
OSGi Runtime
JDK 6

20. HK2 Module System
Abstraction to the module subsystem
No OSGi dependency above HK2 layer
Created to support better GlassFish use cases
Better lazy loading/resolving compared to OSGi Activator/Extender pattern that often require immediate resolution of modules
Service Based Architecture with IoC
Services are injected and injectable
Services annotated interfaces with @Contract
Configuration handling
Binding to XML files
Transactional access
Support validation APIs and MBeans/REST

21. GlassFish and OSGi
Runs on top of OSGi (Felix by default)
Also runs unmodified on Knopflerfish and Equinox
Can be installed in an existing OSGi runtime
GlassFish ships with 200+ bundles in v3
Can run without OSGi (Static mode, thanks to HK2)
Can use OSGi management tools (CLI or Web)
All GlassFish modules are OSGi bundles
No OSGi APIs are used in GlassFish
HK2 provides abstraction layer

22. GlassFish and OSGi
OSGi visibility extended from GlassFish developers to GlassFish users
OSGi services can be easily used in any Java EE application
@Resource(mappedName=”checkOsgiService”)
CheckService checkService;
Client code portable, does not use any OSGi specific API
Restriction: OSGi dynamism does not work
Converged applications needed
Implementation of OSGi Enterprise specifications
HTTP Service, Web Container, JPA, JTA, JDBC

23. Extending GlassFish v3 with OSGi http://blogs. sun
Extend GlassFish with an unmodified Spring dm container
Simple Spring bean implementing the service
Invoke the service from a servlet using standard @Resource injection
Still no use of a GlassFish API
Single runtime for both Spring and full Java EE

24. Managing OSGi Bundles in GlassFish http://blogs. sun
GlassFish CLI
asadmin deploy –type osgi
File system operations
cp/rm to/from glassfish/domains/domain1/autodeploy/bundles
Felix remote shell/gogo shell
telnet localhost 6666
Felix remote shell (GlassFish v3)
Gogo shell(GlassFish 3.1)
provides a scripting environment for administration
Apache Felix web console

25. WAB Lifecycle and Deployments in GlassFish
Java EE deployment on RESOLVED → STARTING
Java EE undeployment on STOPPING → RESOLVED
Alternative WAB Deployments
With OSGi manifest
asadmin deploy --type osgi hybridapp.war
cp hybridapp.war glassfish/modules/autostart
cp hybridapp.war domains/domain1/autodeploy/bundles
Plain WAR file
install webbundle:file://work/webapp/target/hybridapp.war?Web- ContextPath=/hello

26. OSGi/EJB GlassFish feature
Allow EJBs to run within OSGi context
Easily discovered/accessed by other OSGi bundles
Can use container managed JPA
TX, security, persistence contexts propagated
Automatic enlistment of EJBs as OSGi services
Local beans only (SFSB, SLSB, Singleton)
Manifest entry Export-EJB: ALL|NONE
Can split client & service into separate bundles
OSGi ServiceTracker listens for EJB service availability, making deployment order irrelevant

27. OSGi JMS Producer
public class JMSActivator1 implements BundleActivator {
public void start ( BundleContext context ) {
context.registerService ( ManagedService.class.getName(),
new ManagedService() {
public void updated ( Dictionary properties ) {
sendMessage(); }
}, props );
private void sendMessage() {
...
Destination dest = (Destination)
ctx.lookup("jms/osgi.Topic1");
session.createProducer(dest).send(...);
....}}

28. OSGi MDB consumer @MessageDriven(mappedName = "jms/osgi.Topic1")
public class MyMDB implements MessageListener {
public void onMessage(Message message) {
... }

29. CDI Extenstion for OSGi in GlassFish
MyOsgiService svc;
Eliminates boilerplate code in OSGi service clients
For finding, binding and tracking OSGi service references
Typesafe, in contrast to XML based Blueprint Service
Available attributes
Service discovery criteria in standard OSGi Filter syntax
Wait timeout
Dynamic binding for service dynamism through container injected proxy
Applicable in WAB
Since BundleContext is needed

30. All interaction scenarios WAB, EJB module as OSGi service
GlassFish OSGi Demos
JavaOne 2010 Hands-on Lab
All interaction scenarios
WAB, EJB module as OSGi service
OSGi declarative services example
No boilerplate code, automatic OSGi service registration
Maven SCR plugin for OSGi metadata generation
OSGi CDI example
CDI extension for OSGi in GlassFish, applied to a WAB

31. Summary
GlassFish is modular & extensible (HK2/OSGi)
OSGi Declarative Services & CDI OSGi extension
No OSGi API, no GlassFish API, Integration Nirvana!
Hybrid applications bring OSGi benefits to JavaEE (and vice-versa)
Reusable bundles
Independent life-cycles
Standard component models
GlassFish covers all your Java EE and OSGi needs

32. Links OSGi Service Platform Core and Enterprise Specification 4.2
GlassFish
Hybrid application samples

33. GlassFish OSGi - A Modular Runtime for Hybrid Applications
Peter Doschkinow
Senior Java Architect