OSGi DevCon Europe 09 - OSGi on Scala

OSGi on Scala Ease OSGi development with a Scala DSL Heiko Seeberger © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 2009-06-22 Sonntag, 21. Juni 2009

OSGi on Scala Why? • Scala is a great language • Runs on JVM & fully interoperable with Java • Object-functional programming style => Best of OO and FP • Scalable and ﬂexible language => Domain Speciﬁc Languages • Let’s put OSGi on Scala to ease OSGi development © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 2 Sonntag, 21. Juni 2009

OSGi on Scala ScalaModules • Scala DSL for OSGi • Ease service handling • Smooth ugly parts of the API, e.g. null references © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 3 Sonntag, 21. Juni 2009

OSGi on Scala Start Scala REPL with appropriate Classpath tmp$ scala -cp felix.jar:scalamodules-core-...jar:scalamodules-util-...jar Welcome to Scala version 2.7.5.final (Java HotSpot(TM) Client VM, Java 1.5.0_19). Type in expressions to have them evaluated. Type :help for more information. © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 5 Sonntag, 21. Juni 2009

OSGi on Scala Import Felix and ScalaModules scala> import org.apache.felix.framework._ import org.apache.felix.framework._ scala> import org.scalamodules.core.RichBundleContext._ import org.scalamodules.core.RichBundleContext._ © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 6 Sonntag, 21. Juni 2009

OSGi on Scala Start Felix and get BundleContext scala> val felix = new Felix(null) felix: org.apache.felix.framework.Felix = org.apache.felix.framework [0] scala> felix.start scala> val ctx = felix.getBundleContext ctx: org.osgi.framework.BundleContext = org...BundleContextImpl@d9367a © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 7 Sonntag, 21. Juni 2009

OSGi on Scala Deﬁne a Service Interface and Object scala> trait Greeting { def hello: String } defined trait Greeting scala> val greeting = new Greeting { def hello = "Hello!" } greeting: java.lang.Object with Greeting = $anon$1@8ed249 © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 8 Sonntag, 21. Juni 2009

OSGi on Scala Try to consume a Service scala> ctx getOne classOf[Greeting] andApply { _.hello } match { | case Some(s) => println(s) | case None => println("No Greeting service available!") | } No Greeting service available! © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 9 Sonntag, 21. Juni 2009

OSGi on Scala Try to provide a Service with illegal Interface scala> ctx registers classOf[String] theService greeting <console>:13: error: value registers is not a member of org.osgi.framework.BundleContext ctx registers classOf[String] theService greeting ^ © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 10 Sonntag, 21. Juni 2009

OSGi on Scala Provide a Service correctly scala> ctx registerAs classOf[Greeting] theService greeting res3: org.osgi.framework.ServiceRegistration = org...ServiceRegistrationImpl@ed63a3 © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 11 Sonntag, 21. Juni 2009

OSGi on Scala Try to consume a Service once more scala> ctx getOne classOf[Greeting] andApply { _.hello } match { | case Some(s) => println(s) | case None => println("No Greeting service available!") | } Hello! © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 12 Sonntag, 21. Juni 2009

OSGi on Scala Provide a Service with Properties context registerAs classOf[Greeting] withProperties ("name" -> "welcome") theService greeting © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 14 Sonntag, 21. Juni 2009

OSGi on Scala Consume multiple Service applying a Filter context getMany classOf[Greeting] withFilter "(name=*)" andApply { _.welcome } match { case None => noGreetingService() case Some(welcomes) => welcomes.foreach { println } } © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 15 Sonntag, 21. Juni 2009

OSGi on Scala Track Services context track classOf[Greeting] on { case Adding(greeting, _) => println("Adding Greeting: " + greeting.welcome) case Removed(greeting, _) => println("Removed Greeting: " + greeting.goodbye) } © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 16 Sonntag, 21. Juni 2009

OSGi on Scala Service Dependencies context registerAs classOf[Command] dependOn classOf[Greeting] theService { greeting => new Command { ... } } © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 17 Sonntag, 21. Juni 2009

OSGi on Scala How to get started? • www.scalamodules.org • Wiki / Getting Started • Reference Guide • Contact: seeberger@weiglewilczek.com © 2009 WeigleWilczek. Released under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License. 19 Sonntag, 21. Juni 2009

OSGi DevCon Europe 09 - OSGi on Scala

by Heiko Seeberger on Jun 21, 2009

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OSGi DevCon Europe 09 - OSGi on Scala — Presentation Transcript