#1732: Moved splitter and aggregator from Alpakka Docs to Cookbook and … (#31203)

akka-docs/src/test/java/jdocs/stream/javadsl/cookbook/RecipeSplitter.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) since 2016 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+package jdocs.stream.javadsl.cookbook;
+
+import akka.NotUsed;
+import akka.actor.ActorSystem;
+import akka.stream.javadsl.Sink;
+import akka.stream.javadsl.Source;
+import akka.testkit.javadsl.TestKit;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.CompletionStage;
+import java.util.concurrent.ExecutionException;
+
+public class RecipeSplitter {
+    private static ActorSystem system;
+
+    @Test
+    public void simpleSplit() throws ExecutionException, InterruptedException {
+        // #Simple-Split
+        // Sample Source
+        Source<String, NotUsed> source = Source.from(Arrays.asList("1-2-3", "2-3", "3-4"));
+
+        CompletionStage<List<Integer>> ret =
+                source
+                        .map(s -> Arrays.asList(s.split("-")))
+                        .mapConcat(f -> f)
+                        // Sub-streams logic
+                        .map(s -> Integer.valueOf(s))
+                        .runWith(Sink.seq(), system);
+
+        // Verify results
+        List<Integer> list = ret.toCompletableFuture().get();
+        assert list.equals(Arrays.asList(1, 2, 3, 2, 3, 3, 4));
+        // #Simple-Split
+    }
+
+    @Test
+    public void splitAggregate() throws ExecutionException, InterruptedException {
+        // #Aggregate-Split
+        // Sample Source
+        Source<String, NotUsed> source = Source.from(Arrays.asList("1-2-3", "2-3", "3-4"));
+
+        CompletionStage<List<Integer>> ret =
+                source
+                        .map(s -> Arrays.asList(s.split("-")))
+                        // split all messages into sub-streams
+                        .splitWhen(a -> true)
+                        // now split each collection
+                        .mapConcat(f -> f)
+                        // Sub-streams logic
+                        .map(s -> Integer.valueOf(s))
+                        // aggregate each sub-stream
+                        .reduce((a, b) -> a + b)
+                        // and merge back the result into the original stream
+                        .mergeSubstreams()
+                        .runWith(Sink.seq(), system);
+
+        // Verify results
+        List<Integer> list = ret.toCompletableFuture().get();
+        assert list.equals(Arrays.asList(6, 5, 7));
+        // #Aggregate-Split
+    }
+
+    @BeforeClass
+    public static void setup() throws Exception {
+        system = ActorSystem.create();
+    }
+
+    @AfterClass
+    public static void teardown() throws Exception {
+        TestKit.shutdownActorSystem(system);
+    }
+}