Fixed buglet in join binding.

Simplified types for groupByUntil, window, buffer, and empty to use Any and Nothing.

Author: AppliedDuality

language-adaptors/rxjava-scala/src/examples/scala/rx/lang/scala/examples/Olympics.scala

@@ -80,7 +80,7 @@ object Olympics {
     // So we don't use this:
     // Observable.interval(fourYears).take(1).map(i => neverUsedDummyMedal).filter(m => false)
     // But we just return empty, which completes immediately
-    Observable.empty[Medal]
+    Observable.empty
   }
 
 }

language-adaptors/rxjava-scala/src/examples/scala/rx/lang/scala/examples/RxScalaDemo.scala

@@ -243,13 +243,10 @@ class RxScalaDemo extends JUnitSuite {
   }
 
   @Test def groupByUntilExample() {
-    val numbers = Observable.interval(250 millis) take 14
-    val grouped = numbers.groupByUntil[Long, Long](
-      {case x => x % 2},
-      {case (key, obs) => obs filter {case x => x == 7}}
-    )
-    val sequenced = (grouped map {case (key, obs) => obs.toSeq}).flatten
-    sequenced subscribe {x => println(s"Emitted group: $x")}
+    val numbers = Observable.interval(250 millis).take(14)
+    val grouped = numbers.groupByUntil[Long](x => x % 2, {case (key, obs) => obs.filter(x => x == 7)})
+    val sequenced = (grouped.map({ case (key, obs) => obs.toSeq })).flatten
+    sequenced.subscribe(x => println(s"Emitted group: $x"))
   }
 
 
@@ -312,7 +309,7 @@ class RxScalaDemo extends JUnitSuite {
   }
 
   @Test def averageExample() {
-    println(doubleAverage(Observable.empty[Double]).toBlockingObservable.single)
+    println(doubleAverage(Observable.empty).toBlockingObservable.single)
     println(doubleAverage(List(0.0).toObservable).toBlockingObservable.single)
     println(doubleAverage(List(4.44).toObservable).toBlockingObservable.single)
     println(doubleAverage(List(1, 2, 3.5).toObservable).toBlockingObservable.single)

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

@@ -352,10 +352,10 @@ trait Observable[+T]
    * @return
    *         An [[rx.lang.scala.Observable]] which produces buffers which are created and emitted when the specified [[rx.lang.scala.Observable]]s publish certain objects.
    */
-  def buffer[Opening, Closing](openings: Observable[Opening], closings: Opening => Observable[Closing]): Observable[Seq[T]] = {
+  def buffer[Opening](openings: Observable[Opening], closings: Opening => Observable[Any]): Observable[Seq[T]] = {
     val opening: rx.Observable[_ <: Opening] = openings.asJavaObservable
-    val closing: Func1[_ >: Opening, _ <: rx.Observable[_ <: Closing]] = (o: Opening) => closings(o).asJavaObservable
-    val jObs: rx.Observable[_ <: java.util.List[_]] = asJavaObservable.buffer[Opening, Closing](opening, closing)
+    val closing: Func1[_ >: Opening, _ <: rx.Observable[_ <: Any]] = (o: Opening) => closings(o).asJavaObservable
+    val jObs: rx.Observable[_ <: java.util.List[_]] = asJavaObservable.buffer[Opening, Any](opening, closing)
     Observable.jObsOfListToScObsOfSeq(jObs.asInstanceOf[rx.Observable[_ <: java.util.List[T]]])
   }
 
@@ -539,9 +539,9 @@ trait Observable[+T]
    *         An [[rx.lang.scala.Observable]] which produces connected non-overlapping windows, which are emitted
    *         when the current [[rx.lang.scala.Observable]] created with the function argument produces an object.
    */
-  def window[Closing](closings: () => Observable[Closing]): Observable[Observable[T]] = {
-    val func : Func0[_ <: rx.Observable[_ <: Closing]] = closings().asJavaObservable
-    val o1: rx.Observable[_ <: rx.Observable[_]] = asJavaObservable.window[Closing](func)
+  def window(closings: () => Observable[Any]): Observable[Observable[T]] = {
+    val func : Func0[_ <: rx.Observable[_ <: Any]] = closings().asJavaObservable
+    val o1: rx.Observable[_ <: rx.Observable[_]] = asJavaObservable.window[Any](func)
     val o2 = Observable.items(o1).map((x: rx.Observable[_]) => {
       val x2 = x.asInstanceOf[rx.Observable[_ <: T]]
       toScalaObservable[T](x2)
@@ -565,9 +565,9 @@ trait Observable[+T]
    * @return
    *         An [[rx.lang.scala.Observable]] which produces windows which are created and emitted when the specified [[rx.lang.scala.Observable]]s publish certain objects.
    */
-  def window[Opening, Closing](openings: Observable[Opening], closings: Opening => Observable[Closing]) = {
+  def window[Opening](openings: Observable[Opening], closings: Opening => Observable[Any]) = {
     Observable.jObsOfJObsToScObsOfScObs(
-      asJavaObservable.window[Opening, Closing](openings.asJavaObservable, (op: Opening) => closings(op).asJavaObservable))
+      asJavaObservable.window[Opening, Any](openings.asJavaObservable, (op: Opening) => closings(op).asJavaObservable))
       : Observable[Observable[T]] // SI-7818
   }
 
@@ -1335,15 +1335,13 @@ trait Observable[+T]
    *            an observable that emits a single Closing when the group should be closed.
    * @tparam K 
    *            the type of the keys returned by the discriminator function.
-   * @tparam Closing
-   *            the type of the element emitted from the closings observable.
    * @return an Observable that emits `(key, observable)` pairs, where `observable`
    *         contains all items for which `f` returned `key` before `closings` emits a value.
    */
-  def groupByUntil[K, Closing](f: T => K, closings: (K, Observable[T])=>Observable[Closing]): Observable[(K, Observable[T])] = {
-    val fclosing: Func1[_ >: rx.observables.GroupedObservable[K, _ <: T], _ <: rx.Observable[_ <: Closing]] =
+  def groupByUntil[K](f: T => K, closings: (K, Observable[T])=>Observable[Any]): Observable[(K, Observable[T])] = {
+    val fclosing: Func1[_ >: rx.observables.GroupedObservable[K, _ <: T], _ <: rx.Observable[_ <: Any]] =
       (jGrObs: rx.observables.GroupedObservable[K, _ <: T]) => closings(jGrObs.getKey, toScalaObservable[T](jGrObs)).asJavaObservable
-    val o1 = asJavaObservable.groupByUntil[K, Closing](f, fclosing) : rx.Observable[_ <: rx.observables.GroupedObservable[K, _ <: T]]
+    val o1 = asJavaObservable.groupByUntil[K, Any](f, fclosing) : rx.Observable[_ <: rx.observables.GroupedObservable[K, _ <: T]]
     val func = (o: rx.observables.GroupedObservable[K, _ <: T]) => (o.getKey, toScalaObservable[T](o))
     toScalaObservable[(K, Observable[T])](o1.map[(K, Observable[T])](func))
   }
@@ -1353,7 +1351,7 @@ trait Observable[+T]
    * <p>
    * <img width="640" src="https://raw.github.com/wiki/Netflix/RxJava/images/rx-operators/join_.png">
    *
-   * @param inner
+   * @param other
    *          the second Observable to join items from
    * @param leftDurationSelector
    *          a function to select a duration for each item emitted by the source Observable,
@@ -1370,24 +1368,26 @@ trait Observable[+T]
    * @see <a href="https://github.com/Netflix/RxJava/wiki/Combining-Observables#join">RxJava Wiki: join()</a>
    * @see <a href="http://msdn.microsoft.com/en-us/library/hh229750.aspx">MSDN: Observable.Join</a>
    */
-  def join[S, LeftClosing, RightClosing, R] (
-                                              inner: Observable[S],
-                                              leftDurationSelector: T=>Observable[LeftClosing],
-                                              rightDurationSelector: S=>Observable[RightClosing],
-                                              resultSelector: (T,S) => R
-                                              ): Observable[R] = {
+  def join[S, R] (
+      other: Observable[S],
+      leftDurationSelector:  T => Observable[Any],
+      rightDurationSelector: S => Observable[Any],
+      resultSelector: (T,S) => R
+  ): Observable[R] = {
 
     val outer : rx.Observable[_ <: T] = this.asJavaObservable
-    val left:  Func1[_ >: T, _<: rx.Observable[_ <: LeftClosing]] =   (t: T) => leftDurationSelector(t).asJavaObservable
-    val right: Func1[_ >: S, _<: rx.Observable[_ <: RightClosing]] =  (s: S) => rightDurationSelector(s).asJavaObservable
-
-    val o1 = outer.asInstanceOf[rx.Observable[T]].join[S, LeftClosing, RightClosing, R](
-      inner.asJavaObservable.asInstanceOf[rx.Observable[S]],
-      left. asInstanceOf[Func1[T, rx.Observable[LeftClosing]]],
-      right.asInstanceOf[Func1[S, rx.Observable[RightClosing]]],
-      resultSelector.asInstanceOf[Func2[T,S,R]])
-
-    toScalaObservable[R](o1)
+    val inner : rx.Observable[_ <: S] = other.asJavaObservable
+    val left:  Func1[_ >: T, _<: rx.Observable[_ <: Any]] =   (t: T) => leftDurationSelector(t).asJavaObservable
+    val right: Func1[_ >: S, _<: rx.Observable[_ <: Any]] =  (s: S) => rightDurationSelector(s).asJavaObservable
+    val f: Func2[_>: T, _ >: S, _ <: R] = resultSelector
+
+    toScalaObservable[R](
+      outer.asInstanceOf[rx.Observable[T]].join[S, Any, Any, R](
+        inner.asInstanceOf[rx.Observable[S]],
+        left. asInstanceOf[Func1[T, rx.Observable[Any]]],
+        right.asInstanceOf[Func1[S, rx.Observable[Any]]],
+        f.asInstanceOf[Func2[T,S,R]])
+    )
   }
 
   /**
@@ -2177,18 +2177,15 @@ object Observable {
    * <p>
    * <img width="640" src="https://raw.github.com/wiki/Netflix/RxJava/images/rx-operators/empty.s.png">
    *
-   * @param scheduler the scheduler to call the
-                        [[rx.lang.scala.Observer#onCompleted onCompleted]] method
-   * @param T the type of the items (ostensibly) emitted by the Observable
    * @return an Observable that returns no data to the [[rx.lang.scala.Observer]] and
    *         immediately invokes the [[rx.lang.scala.Observer]]r's
    *        [[rx.lang.scala.Observer#onCompleted onCompleted]] method with the
    *         specified scheduler
    * @see <a href="https://github.com/Netflix/RxJava/wiki/Creating-Observables#empty-error-and-never">RxJava Wiki: empty()</a>
    * @see <a href="http://msdn.microsoft.com/en-us/library/hh229066.aspx">MSDN: Observable.Empty Method (IScheduler)</a>
    */
-  def empty[T]: Observable[T] = {
-    toScalaObservable(rx.Observable.empty[T]())
+  def empty: Observable[Nothing] = {
+    toScalaObservable(rx.Observable.empty[Nothing]())
   }
 
   /**
@@ -2200,16 +2197,15 @@ object Observable {
    *
    * @param scheduler the scheduler to call the
                         [[rx.lang.scala.Observer#onCompleted onCompleted]] method
-   * @param T the type of the items (ostensibly) emitted by the Observable
    * @return an Observable that returns no data to the [[rx.lang.scala.Observer]] and
    *         immediately invokes the [[rx.lang.scala.Observer]]r's
    *        [[rx.lang.scala.Observer#onCompleted onCompleted]] method with the
    *         specified scheduler
    * @see <a href="https://github.com/Netflix/RxJava/wiki/Creating-Observables#empty-error-and-never">RxJava Wiki: empty()</a>
    * @see <a href="http://msdn.microsoft.com/en-us/library/hh229066.aspx">MSDN: Observable.Empty Method (IScheduler)</a>
    */
-  def empty[T](scheduler: Scheduler): Observable[T] = {
-    toScalaObservable(rx.Observable.empty[T](scalaSchedulerToJavaScheduler(scheduler)))
+  def empty(scheduler: Scheduler): Observable[Nothing] = {
+    toScalaObservable(rx.Observable.empty[Nothing](scalaSchedulerToJavaScheduler(scheduler)))
   }
 
   /**

language-adaptors/rxjava-scala/src/test/scala/rx/lang/scala/ObservableTest.scala

@@ -123,6 +123,13 @@ class ObservableTests extends JUnitSuite {
     assertEquals(6, o.toBlockingObservable.single)
   }
 
+  @Test def testJoin() {
+     val xs = Observable.items(1,2,3)
+     val ys = Observable.items("a")
+     val zs = xs.join[String,String](ys, x => Observable.never, y => Observable.never, (x,y) => y+x)
+     assertEquals(List("a1", "a2", "a3"),zs.toBlockingObservable.toList)
+  }
+
   /*
  @Test def testHead() {
    val observer = mock(classOf[Observer[Int]])