Adds example for lastOption operator akka#25468

mehdimousavi1995 · Oct 15, 2018 · 531b645 · 531b645
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Showing 4 changed files with 43 additions and 21 deletions.
diff --git a/akka-docs/src/main/paradox/stream/operators/Sink/lastOption.md b/akka-docs/src/main/paradox/stream/operators/Sink/lastOption.md
@@ -27,3 +27,10 @@ completed with @scala[`None`] @java[an empty `Optional`].
 
 @@@
 
+## Example
+
+Scala
+:   @@snip [LastSinkSpec.scala](/akka-stream-tests/src/test/scala/akka/stream/scaladsl/LastSinkSpec.scala) { #lastOption-operator-example }
+
+Java
+:   @@snip [SinkDocExamples.java](/akka-docs/src/test/java/jdocs/stream/operators/SinkDocExamples.java) { #lastOption-operator-example }
diff --git a/akka-docs/src/test/java/jdocs/stream/operators/SinkDocExamples.java b/akka-docs/src/test/java/jdocs/stream/operators/SinkDocExamples.java
@@ -6,6 +6,7 @@
 
 import akka.NotUsed;
 import akka.actor.ActorSystem;
+import akka.japi.Pair;
 import akka.stream.ActorMaterializer;
 import akka.stream.Materializer;
 import akka.stream.javadsl.Sink;
@@ -37,27 +38,27 @@ static void reduceExample() throws InterruptedException, ExecutionException, Tim
     static void takeLastExample() throws InterruptedException, ExecutionException, TimeoutException {
         //#takeLast-operator-example
         // tuple of (Name, GPA)
-        List<Tuple2> sortedStudents = Arrays.asList(new Tuple2("Benita", 2.1), new Tuple2("Adrian", 3.1),
-                new Tuple2("Alexis", 4), new Tuple2("Kendra", 4.2), new Tuple2("Jerrie", 4.3), new Tuple2("Alison", 4.7));
+        List<Pair> sortedStudents = Arrays.asList(new Pair<>("Benita", 2.1), new Pair<>("Adrian", 3.1),
+                new Pair<>("Alexis", 4), new Pair<>("Kendra", 4.2), new Pair<>("Jerrie", 4.3), new Pair<>("Alison", 4.7));
 
-        Source<Tuple2, NotUsed> studentSource = Source.from(sortedStudents);
+        Source<Pair, NotUsed> studentSource = Source.from(sortedStudents);
 
-        CompletionStage<List<Tuple2>> topThree = studentSource.runWith(Sink.takeLast(3), materializer);
+        CompletionStage<List<Pair>> topThree = studentSource.runWith(Sink.takeLast(3), materializer);
 
-        List<Tuple2> result = topThree.toCompletableFuture().get(3, TimeUnit.SECONDS);
+        List<Pair> result = topThree.toCompletableFuture().get(3, TimeUnit.SECONDS);
 
         System.out.println("#### Top students ####");
         for (int i = result.size() - 1; i >= 0; i--) {
-            Tuple2<String, Double> s = result.get(i);
-            System.out.println("Name: " + s._1 + ", " + "GPA: " + s._2);
+            Pair<String, Double> s = result.get(i);
+            System.out.println("Name: " + s.first() + ", " + "GPA: " + s.second());
         }
         /*
         #### Top students ####
         Name: Alison, GPA: 4.7
         Name: Jerrie, GPA: 4.3
         Name: Kendra, GPA: 4.2
       */
-      //#takeLast-operator-example
+        //#takeLast-operator-example
     }
 
     static void lastExample() throws InterruptedException, ExecutionException, TimeoutException {
@@ -70,4 +71,13 @@ static void lastExample() throws InterruptedException, ExecutionException, Timeo
         //#last-operator-example
     }
 
+    static void lastOptionExample() throws InterruptedException, ExecutionException, TimeoutException {
+        //#lastOption-operator-example
+        Source<Integer, NotUsed> source = Source.empty();
+        CompletionStage<Optional<Integer>> result = source.runWith(Sink.<Integer>lastOption(), materializer);
+        Optional<Integer> optItem = result.toCompletableFuture().get(3, TimeUnit.SECONDS);
+        System.out.println(optItem);
+        // Optional.empty
+        //#lastOption-operator-example
+    }
 }
diff --git a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/LastSinkSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/LastSinkSpec.scala
@@ -1,30 +1,29 @@
 /**
- * Copyright (C) 2014-2018 Lightbend Inc. <https://www.lightbend.com>
- */
+  * Copyright (C) 2014-2018 Lightbend Inc. <https://www.lightbend.com>
+  */
 
 package akka.stream.scaladsl
 
-import scala.concurrent.Await
-import scala.concurrent.duration._
-
-import akka.stream.ActorMaterializer
-import akka.stream.ActorMaterializerSettings
+import akka.stream.{ActorMaterializer, ActorMaterializerSettings}
 import akka.stream.testkit._
-import akka.stream.testkit.Utils._
 import akka.stream.testkit.scaladsl.StreamTestKit._
 
+import scala.concurrent.duration._
+import scala.concurrent.{Await, Future}
+
 class LastSinkSpec extends StreamSpec with ScriptedTest {
 
   val settings = ActorMaterializerSettings(system)
 
   implicit val materializer: ActorMaterializer = ActorMaterializer(settings)
+  implicit val ec = system.dispatcher
 
   "A Flow with Sink.last" must {
 
-    "yield the last value" in  {
+    "yield the last value" in {
       //#last-operator-example
       val source = Source(1 to 10)
-      val result = source.runWith(Sink.last)
+      val result: Future[Int] = source.runWith(Sink.last)
       result.map(println)
       // 10
       //#last-operator-example
@@ -58,8 +57,14 @@ class LastSinkSpec extends StreamSpec with ScriptedTest {
       } should be theSameInstanceAs (ex)
     }
 
-    "yield None for empty stream" in assertAllStagesStopped {
-      Await.result(Source.empty[Int].runWith(Sink.lastOption), 1.second) should be(None)
+    "yield None for empty stream" in {
+      //#lastOption-operator-example
+      val source = Source.empty[Int]
+      val result: Future[Option[Int]] = source.runWith(Sink.lastOption)
+      result.map(println)
+      // None
+      //#lastOption-operator-example
+      result.futureValue shouldEqual None
     }
 
   }

diff --git a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/TakeLastSinkSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/TakeLastSinkSpec.scala
@@ -35,7 +35,7 @@ class TakeLastSinkSpec extends StreamSpec {
 
       val sourceOfStudents = Source(students)
 
-      val result = sourceOfStudents.runWith(Sink.takeLast(3))
+      val result: Future[Seq[Student]] = sourceOfStudents.runWith(Sink.takeLast(3))
 
       result.foreach { topThree ⇒
         println("#### Top students ####")