rename akka-docs dir to docs (#62)

docs/src/test/java/jdocs/stream/javadsl/cookbook/RecipeSourceFromFunction.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2015-2022 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+package jdocs.stream.javadsl.cookbook;
+
+import org.apache.pekko.NotUsed;
+import org.apache.pekko.actor.ActorSystem;
+import org.apache.pekko.stream.javadsl.Sink;
+import org.apache.pekko.stream.javadsl.Source;
+import org.apache.pekko.testkit.javadsl.TestKit;
+import com.typesafe.config.ConfigFactory;
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.util.List;
+import java.util.UUID;
+import java.util.concurrent.TimeUnit;
+
+public class RecipeSourceFromFunction extends RecipeTest {
+  static ActorSystem system;
+
+  @BeforeClass
+  public static void setup() {
+    system =
+        ActorSystem.create(
+            "RecipeSourceFromFunction",
+            ConfigFactory.parseString(
+                "akka.loglevel=DEBUG\nakka.loggers = [org.apache.pekko.testkit.TestEventListener]"));
+  }
+
+  @AfterClass
+  public static void tearDown() {
+    TestKit.shutdownActorSystem(system);
+    system = null;
+  }
+
+  @Test
+  public void beMappingOfRepeat() throws Exception {
+    new TestKit(system) {
+      final String builderFunction() {
+        return UUID.randomUUID().toString();
+      }
+
+      {
+        // #source-from-function
+        final Source<String, NotUsed> source =
+            Source.repeat(NotUsed.getInstance()).map(elem -> builderFunction());
+        // #source-from-function
+
+        final List<String> result =
+            source
+                .take(2)
+                .runWith(Sink.seq(), system)
+                .toCompletableFuture()
+                .get(3, TimeUnit.SECONDS);
+
+        Assert.assertEquals(2, result.size());
+      }
+    };
+  }
+}