Merge pull request #1160 from zsxwing/replay-multicast

Add `replay` and `multicast` variants to RxScala

Author: benjchristensen

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

@@ -343,14 +343,54 @@ class RxScalaDemo extends JUnitSuite {
 
   @Test def exampleWithReplay() {
     val numbers = Observable.interval(1000 millis).take(6)
-    val (startFunc, sharedNumbers) = numbers.replay
+    val sharedNumbers = numbers.replay
     sharedNumbers.subscribe(n => println(s"subscriber 1 gets $n"))
-    startFunc()
+    sharedNumbers.connect
     // subscriber 2 subscribes later but still gets all numbers
     doLater(3500 millis, () => { sharedNumbers.subscribe(n => println(s"subscriber 2 gets $n")) })
     waitFor(sharedNumbers)
   }
 
+  @Test def exampleWithReplay2() {
+    val numbers = Observable.interval(100 millis).take(10)
+    val sharedNumbers = numbers.replay(3)
+    sharedNumbers.subscribe(n => println(s"subscriber 1 gets $n"))
+    sharedNumbers.connect
+    // subscriber 2 subscribes later but only gets the 3 buffered numbers and the following numbers
+    Thread.sleep(700)
+    sharedNumbers.subscribe(n => println(s"subscriber 2 gets $n"))
+    waitFor(sharedNumbers)
+  }
+
+  @Test def exampleWithReplay3() {
+    val numbers = Observable.interval(100 millis).take(10)
+    val sharedNumbers = numbers.replay(300 millis)
+    sharedNumbers.subscribe(n => println(s"subscriber 1 gets $n"))
+    sharedNumbers.connect
+    // subscriber 2 subscribes later but only gets the buffered numbers and the following numbers
+    Thread.sleep(700)
+    sharedNumbers.subscribe(n => println(s"subscriber 2 gets $n"))
+    waitFor(sharedNumbers)
+  }
+
+  @Test def exampleWithReplay4() {
+    val numbers = Observable.interval(100 millis).take(10)
+    val sharedNumbers = numbers.replay(2, 300 millis)
+    sharedNumbers.subscribe(n => println(s"subscriber 1 gets $n"))
+    sharedNumbers.connect
+    // subscriber 2 subscribes later but only gets the buffered numbers and the following numbers
+    Thread.sleep(700)
+    sharedNumbers.subscribe(n => println(s"subscriber 2 gets $n"))
+    waitFor(sharedNumbers)
+  }
+
+  @Test def exampleWithReplay5() {
+    val numbers = Observable.interval(100 millis).take(10)
+    val sharedNumbers = numbers.replay[Long, Long]((o: Observable[Long]) => o.map(_ * 2))
+    sharedNumbers.subscribe(n => println(s"subscriber gets $n"))
+    waitFor(sharedNumbers)
+  }
+
   @Test def testSingleOption() {
     assertEquals(None,    List(1, 2).toObservable.toBlockingObservable.singleOption)
     assertEquals(Some(1), List(1).toObservable.toBlockingObservable.singleOption)
@@ -720,7 +760,7 @@ class RxScalaDemo extends JUnitSuite {
   }
 
   @Test def repeatExample1(): Unit = {
-    val o : Observable[String] = List("alice", "bob", "carol").toObservable.repeat().take(6)
+    val o : Observable[String] = List("alice", "bob", "carol").toObservable.repeat.take(6)
     assertEquals(List("alice", "bob", "carol", "alice", "bob", "carol"), o.toBlockingObservable.toList)
   }
 
@@ -802,6 +842,21 @@ class RxScalaDemo extends JUnitSuite {
     }
   }
 
+  @Test def multicastExample1(): Unit = {
+    val unshared = Observable.from(1 to 4)
+    val shared = unshared.multicast(Subject())
+    shared.subscribe(n => println(s"subscriber 1 gets $n"))
+    shared.subscribe(n => println(s"subscriber 2 gets $n"))
+    shared.connect
+  }
+
+  @Test def multicastExample2(): Unit = {
+    val unshared = Observable.from(1 to 4)
+    val shared = unshared.multicast[Int, String](() => Subject(), o => o.map("No. " + _))
+    shared.subscribe(n => println(s"subscriber 1 gets $n"))
+    shared.subscribe(n => println(s"subscriber 2 gets $n"))
+  }
+
   @Test def startWithExample(): Unit = {
     val o1 = List(3, 4).toObservable
     val o2 = 1 +: 2 +: o1