Frankenstein's IDE: NetBeans and OSGi

Frankenstein's IDE Anton Epple Eppleton IT Consulting http://www.eppleton.de Frankenstein's IDE: Running NetBeans on OSGi and vice versa

Agenda

Module Systems
Service Infrastructure
Project netigso: bringing it all together
Demos

Modularity Recap: Why a module system? Standard Java doesn't support:

Versioning
Plugins & Updates
Dynamic Service Infrastructure
Dependency management
Controlled API export (information hiding)

Module Systems like OSGi & NetBeans Module System add this

Modularity NetBeans Module System? Started in 1996:

Foundation of the IDE ( first NetBeans release 1999 )
Usable as independent platform for many years
Used on client & server
Many commercial and institutional users ( Nokia, Boeing, UNESCO, EADS, US Army ... )

Duke's Choice Award 2009

Duke's Choice Award 2009 What's the difference between OSGi and NB Platform?

Module System How does the OSGi module system work?

Runtime Container manages Life cycle and dependencies of modules
Basic Services provide reusable functionality
API/SPI Modules provide Extension Points and Utility Classes
User Modules provide application functionality

Module System How does the NetBeans module system work?

Runtime Container manages Life cycle and dependencies of modules
Basic Services provide reusable functionality
API/SPI Modules provide Extension Points and Utility Classes
User Modules provide application functionality

Module System How does the OSGi module system work?

Runtime starts up reads meta information and sets up dependencies
Starts the Modules
ClassLoader: Every Module has it's own classloader. It can only load classes from other Modules if it has declared a dependency. Loading is then delegated to the other modules ClassLoader

Module System How does the NetBeans module system work?

Runtime starts up reads meta information and sets up dependencies
Starts the Modules
ClassLoader: Every Module has it's own classloader. It can only load classes from other Modules if it has declared a dependency. Loading is then delegated to the other modules ClassLoader
Tip : Cross-check mailing list for third-party lib problems

Module System How is a OSGi bundle constructed?

Module is a JAR Archive containing:

META-INF/MANIFEST.MF

Id
Version
Public API
Dependencies

Service registration

Module System How is a NetBeans module constructed?

Module is a JAR Archive containing:

META-INF/MANIFEST.MF

Id
Version
Public API
Dependencies

Service registration

Module System Meta-Data: NetBeans OSGi Identifier OpenIDE-Module: X Bundle-SymbolicName: X Version number OpenIDE-Module-Specification-Version: 7.3 Bundle-Version: 7.3 Activator OpenIDE-Module-Install: x.y.z.Activator Bundle-Activator: x.y.z.Activator Exported Packages OpenIDE-Module-Public-Packages: x.y.z Export-Package: x.y.z Imported Dependencies OpenIDE-Module-Module-Dependencies: another.module > 2.1 Require-Bundle: another.module;bundle-version="(2.1 )"

Module System Conclusion: Great minds think alike … but not always

OSGi Specific to OSGi / Equinox:

Bundles have different states:

Installed
Resolved
Started

Eclipse: Buddy Policies ( dependent, global, app, ext, boot, registered = allow circular classloading dependencies for third party libs)

OSGi Specific to NetBeans:

Tokens for declaring Service Dependencies:

Requires
Provides...

Demo LookupSample:

OpenIDE-Module-Requires: de.eppleton.extensionpointinterface.MessageProviderInterface OpenIDE-Module-Provides: de.eppleton.extensionpointinterface.MessageProviderInterface

Agenda

Module Systems
Demos

OSGi:

OSGi Services
Dynamic Services
Declarative Services
Eclipse Extension Points
...

Service Infrastructure NetBeans Platform :

Lookup

Registration based on Java Standards (JAR Spec & ServiceLoader)
+ Listening for Changes
+ Lazy Loading
+ Ordering

Service Infrastructure NetBeans Platform :

Registry (System FileSystem)

Per module XML file
Extension points are folders in the FileSystem
Extensions are virtual files in the FileSystem
Files can represent resources or instances
Parametrized instantiation, Factory classes & methods

Lookups + SFS = NetBeans Service Infrastructure

Service Infrastructure NetBeans Extension Points :

Extensions are declarations
One extension can contribute to an indefinite number of Extension points
Extension point definer queries registry when needed ( lazy loading )
Extensions need not be associated with executable Java code

Comparison OSGi & NetBeans Services:

-> NB Services very flexible, but not self documented

NetBeans Declarative Services Extension Points 1 Service can contribute to more than one Extension Point + + - No need to implement interface + - + Metadata for Documentation - ApiDoc + +

Agenda

Modular Systems
Demos

Motivation Why would I want an additional Module System?

Use the same bundles on client and server
OSGi 4.2 Distributed OSGi: Use the same code to work with local and remote services

Project Netigso Netigso:

Felix OSGi container embedded in NetBeans

Interoperability for NetBeans Modules ↔ OSGi bundles

Dependency Management over system boundaries

Final target: Make platform interchangeable
http://wiki.netbeans.org/OSGiAndNetBeans

Creates Bundles/Modules in NetBeans (build harness)

Demo Hello World Demo:

Creating a Bundle with Netigso

NB understands both types of metadata: Setting dependencies between Modules and bundles possible

Demo Interoperability Demo:

Creating a Module that uses classes from OSGi bundle

Project Netigso Service Interoperability:

Bundles can contribute to NB Extension points
XML registry & Lookup works

Project Netigso Runtime: When a bundle is available, launch embedded felix: configMap.put("felix.cache.profiledir", cache); configMap.put("felix.cache.dir", cache); configMap.put(Constants.FRAMEWORK_STORAGE, cache); activator = new NetigsoActivator(); // listen to changes List<BundleActivator> activators = new ArrayList<BundleActivator>(); activators.add(activator); configMap.put("felix.systembundle.activators", activators); felix = new Felix(configMap); felix.init();

Project Netigso Expose all Modules as bundles to felix: private static final InputStream fakeBundle(Module m) throws IOException { // create in memory jar containing manifest for OSGi container ByteArrayOutputStream os = new ByteArrayOutputStream(); Manifest man = new Manifest(); man.getMainAttributes().putValue("Manifest-Version", "1.0"); man.getMainAttributes().putValue("Bundle-ManifestVersion", "2"); .... JarOutputStream jos = new JarOutputStream(os, man); jos.close(); return new ByteArrayInputStream(os.toByteArray()); } // later inject the Module ClassLoader into the Bundle

Project Netigso Expose all Bundles as Modules to Module system: final class NetigsoModule extends Module { final Bundle bundle; private NetigsoLoader loader; ... @Override public String getCodeName() { return bundle.getSymbolicName(); } @Override public String getCodeNameBase() { return bundle.getSymbolicName(); } ...

Agenda

Recap: Modularity
OSGi
Project Netigso
Demo

Demo Importing Bundles Demo:

ant -f $NETIGSO/harness/suite.xml clusterize -Dcluster=plugins -Dincludes=modules/**
Example: Felix Remote Shell
Diagnosis and Management Tool
telnet localhost 6666
Installing and uninstalling bundles

Demo Eclipse Equinox Bundles Demo:

Peter Kriens SUDOKU example:
HTTPService serves SUDOKU game
RPC Layer for communication between JavaScript frontend and server
Based on Eclipse Equinox
In Suite add to project.properties: run.args.extra=--nosplash -J-Dorg.osgi.service.http.port=8080

Lessons Learned Lessons learned

OSGi & NB Module system are very similar and interoperable
Problems:

Equinox core bundle contains helper classes

Package import vs required bundles

Services are standardized, but versioning isn't:

Two bundles implementing the same service can have totally independent version numbers in different OSGi containers => Service implementations not easily interchangeable

Demo Distributed OSGi Hello World Demo: