make Subscription an implicit value class

Author: samuelgruetter

language-adaptors/rxjava-scala/src/main/scala/rx/lang/scala/ImplicitFunctionConversions.scala

@@ -29,8 +29,8 @@ object ImplicitFunctionConversions {
 
   implicit def scalaFunction1ToOnSubscribeFunc[T](f: rx.lang.scala.Observer[T] => Subscription) =
     new rx.Observable.OnSubscribeFunc[T] {
-      def onSubscribe(obs: Observer[_ >: T]): Subscription = {
-        f(obs)
+      def onSubscribe(obs: Observer[_ >: T]): rx.Subscription = {
+        f(obs).asJava
       }
     }
 

language-adaptors/rxjava-scala/src/main/scala/rx/lang/scala/package.scala

@@ -35,8 +35,20 @@ package object scala {
 
   type Observer[-T] = rx.Observer[_ >: T]  
   type Scheduler = rx.Scheduler
-  type Subscription = rx.Subscription
 
+  /**
+   * Subscriptions are returned from all Observable.subscribe methods to allow unsubscribing.
+   * 
+   * This interface is the RxJava equivalent of IDisposable in Microsoft's Rx implementation.
+   */
+  implicit class Subscription(val asJava: rx.Subscription) extends AnyVal {
+    /**
+     * Call this to stop receiving notifications on the Observer that was registered when 
+     * this Subscription was received.
+     */
+    def unsubscribe(): Unit = asJava.unsubscribe()
+  }
+
 }
 
 /*