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OSGi: Final summary and discussion https://osgi/

OSGi: Final summary and discussion https://www.osgi.org/. Outline. Review: Origins of OSGi Consortium Goals Review: What is OSGi Dynamic Modules for Java Advanced Component Models over OSGi OSGi adoption in practice and success stories Application servers Eclipse Eclipse plug-ins

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OSGi: Final summary and discussion https://osgi/

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  1. OSGi: Final summary and discussionhttps://www.osgi.org/

  2. Outline • Review: Origins of OSGi • Consortium • Goals • Review: What is OSGi • Dynamic Modules for Java • Advanced Component Models over OSGi • OSGi adoption in practice and success stories • Application servers • Eclipse • Eclipse plug-ins • OSGi criticism

  3. Review: The OSGi Alliance • OSGi is a set of specifications by the OSGi-Alliance • The Open Service Gateway Initiative • Initial goal: Facilitate the componentization of software and assure remote management and interoperability of applications and services over a broad variety of devices • Application domains: Home automation, Mobile devices, Enterprise applications • Current members of the OSGi alliance: • Strategic members: Adobe,  Deutsche Telekom, Hitachi,  IBM,  Liferay, NTT,  Oracle, Paremus, Ltd., ProSyst Software,  Salesforce.com, Software AG , TIBCO • Principal members: Cloudyle, Luminis,  Makewave,   Sumitomo Electric Industries, Ltd. • Contributing associates: Eclipse Foundation, Inc.,  Intuit Inc., Mitsubishi Electric, NEC, Orange, Red Hat,  Sagemcom SAS, Schneider Electric, Telecom Italia S.p.A, Unify GmbH & Co. KG 

  4. OSGi specifications • developed in expert groups • Core platform (CPEG) • Vehicle (VEG) OSGi in vehicles • Mobile (MEG) OSGi in mobile devices • Enterprise (EEG) OSGi in enterprise solutions • Residential (REG) OSGi in home automation • structured into 2 documents • Core Specification : framework • Service Compendium : standard services

  5. OSGi specification releases • OSGi Release 1 (R1): May 2000 • OSGi Release 2 (R2): October 2001 • OSGi Release 3 (R3): March 2003 • OSGi Release 4 (R4): October 2005 / September 2006 • Core Specification (R4 Core): October 2005 • Mobile Specification (R4 Mobile / JSR-232): September 2006 • OSGi Release 4.1 (R4.1): May 2007 (AKA JSR-291) • OSGi Release 4.2 (R4.2): September 2009 • Enterprise Specification (R4.2): March 2010 • OSGi Release 4.3 (R4.3): April 2011 • Core: April 2011 • Compendium and Residential: May 2012 • OSGi Release 5 (R5): June 2012 • Core and Enterprise: June 2012 • OSGi Release 6: July 2014

  6. Review: What is OSGi now • OSGi = Dynamic Modules for Java • A set ofspecifications of the OSGi Alliance (currently Release 6) • A set of different implementations of these specifications • Equinox, Felix, Knopplerfish • Advanced component models over OSGi, developed independently by external parties (not included in OSGi specifications) • iPOJO, Spring DM

  7. Review: OSGI – a component framework for Java Bundle Bundle Bundle Bundle Bundle OSGi Framework Java Runtime Environment (JRE) Operating System (OS) Hardware

  8. Review: OSGI Layered Architecture Service Bundles Lifecycle Module Execution Environment HW / OS

  9. Review: Greeting Example - Modules org.foo.hello.helper Helper org.foo.hello org.foo.hello.cli import Client Greeting export org.foo.hello Import org.foo.hello

  10. Review: Greeting Example - Services org.foo.hello Greeting org.foo.hello import org.foo.hello.cli Client get Import org.osgi.* org.foo.hello.impl Activator GreetingImpl Import org.osgi.* Activator register

  11. Review: Greeting Example - with DS GreetingImpl1 IGreeting GreetingConsumer IGreeting [0..n] GreetingImpl2 IGreeting

  12. OSGi adoption • The OSGi component system is used to build highly complex applications like: • IDE’s, application servers, application frameworks, telecom and service solutions, industrial automation, residential gateways, onboard telematics systems,  etc

  13. Java EE application servers • vendors look for ways to make their application server products more modular and flexible • IBM's WebSphere • Red Hat’s JBoss • Oracle’s GlassFish Enterprise Server • ObjectWeb’s JOnAS, and • Apache’s Geronimo

  14. Eclipse • Eclipse: an open development platform comprised of extensible frameworks, tools and runtimes for building, deploying and managing software across the lifecycle

  15. Eclipse architecture Figure from: http://www.hs-augsburg.de/~meixner/saj/skript/osgi/eclipseplugins.html

  16. Different types of Eclipse plug-ins • C++ IDE (CDE) • Visual UI Editor (SWT/Swing Designer) • UML modeling tools • Colaborative tools (SVN) • Aspect oriented language extension (AspectJ)

  17. Eclipse plug-ins • All written in Java • Found at Eclipse launch - can not dynamically swap plug-ins • Load-on-demand strategy - makes it possible to have many different plug-ins and still manage to obtain reasonable performance

  18. Multi-layered extensibility: Plugins, Extension points, Extensions Eclipse plug-in architecture Figure from: http://www.hs-augsburg.de/~meixner/saj/skript/osgi/eclipseplugins.html

  19. Create an Eclipse HelloWorld plugin • Example: create an Eclipse plugin that adds a new Menu entry; when activated, it displays a window with a message • Eclipse -> New ->Project • Project wizard -> Plug-in-project -> select target = Eclipse • Select Create plugin using one of the templates -> Plugin with a popup menu • Generated files: • Source code: Activator.java, SampleAction.java • Metadata: MANIFEST.MF, plugin.xml • You may already run the plugin (Run As -> Eclipse Application)

  20. Manifest file for HelloWorld example Manifest-Version: 1.0 Bundle-ManifestVersion: 2 Bundle-Name: Myeclipseplugin Bundle-SymbolicName: org.foo.myeclipseplugin; singleton:=true Bundle-Version: 1.0.0.qualifier Bundle-Activator: org.foo.myeclipseplugin.Activator Require-Bundle: org.eclipse.ui, org.eclipse.core.runtime, org.eclipse.core.resources Bundle-ActivationPolicy: lazy Bundle-RequiredExecutionEnvironment: JavaSE-1.7 An Eclipse plugin is an OSGi bundle !

  21. OSGi for Eclipse Developers

  22. org.foo.myeclipseplugin.Activator publicclass Activator extends AbstractUIPlugin { publicstaticfinal String PLUGIN_ID = "org.foo.myeclipseplugin"; privatestatic Activator plugin; public Activator() { } publicvoid start(BundleContext context) throws Exception { super.start(context); plugin = this; } publicvoid stop(BundleContext context) throws Exception { plugin = null; super.stop(context); } publicstatic Activator getDefault() { returnplugin; } publicstatic ImageDescriptor getImageDescriptor(String path) { returnimageDescriptorFromPlugin(PLUGIN_ID, path); } }

  23. Two manifest files MANIFEST.MF plugin.xml • Classical OSGi manifest: • Bundle identification • Dependencies • Activator • Extension points • Extensions

  24. Plugin.xml for HelloWorld example <?xml version="1.0" encoding="UTF-8"?> <?eclipse version="3.4"?> <plugin> <extension point="org.eclipse.ui.popupMenus"> <objectContribution objectClass="org.eclipse.core.resources.IFile" id="org.foo.myeclipseplugin.contribution1"> <menu label="New Submenu" path="additions" id="org.foo.myeclipseplugin.menu1"> <separator name="group1"> </separator> </menu> <action label="New Action" class="org.foo.myeclipseplugin.popup.actions.NewAction" menubarPath="org.foo.myeclipseplugin.menu1/group1" enablesFor="1" id="org.foo.myeclipseplugin.newAction"> </action> </objectContribution> </extension> </plugin>

  25. org.foo.myeclipseplugin. popup.actions.NewAction package org.foo.myeclipseplugin.popup.actions; public class NewAction implements IObjectActionDelegate { private Shell shell; public NewAction() { super(); } public void setActivePart(IAction action, IWorkbenchPart targetPart) { shell = targetPart.getSite().getShell(); } public void run(IAction action) { MessageDialog.openInformation( shell, "Myeclipseplugin", "New Action was executed."); } public void selectionChanged(IAction action, ISelection selection) {} }

  26. OSGi Criticism • Most of the success stories of OSGi adoption are with (dynamic) plug-in architectures • OSGi is suited for applications where modularityand dynamic extensibility are particularly  important • OSGi may be too complex if the interest is on modularity only • Using independent Java libraries (available as “normal” jars) from OSGi applications is difficult • JRE will not adopt OSGi: if the JRE will be organized in a modular way, this will have to come from itself, not from an external container

  27. Java modularity alternatives • Goals: • Introducing the concept of module for programmers • Refactoring of the JDK/ JRE in a modular way (current JRE is monolithic) • Project Jigsaw: has as a goal to design and implement a standard module system for the Java SE Platform, and to apply that system to the Platform itself and to the JDK. • It was postponed many times, it is now planned for java 9 

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