rename akka-docs dir to docs (#62)

docs/src/test/java/jdocs/stream/QuickStartDocTest.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2016-2022 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+package jdocs.stream;
+
+// #stream-imports
+import org.apache.pekko.stream.*;
+import org.apache.pekko.stream.javadsl.*;
+// #stream-imports
+
+// #other-imports
+import org.apache.pekko.Done;
+import org.apache.pekko.NotUsed;
+import org.apache.pekko.actor.ActorSystem;
+import org.apache.pekko.util.ByteString;
+
+import java.nio.file.Paths;
+import java.math.BigInteger;
+import java.time.Duration;
+import java.util.concurrent.CompletionStage;
+import java.util.concurrent.ExecutionException;
+// #other-imports
+
+import jdocs.AbstractJavaTest;
+
+import org.junit.*;
+
+/**
+ * This class is not meant to be run as a test in the test suite, but it is set up such that it can
+ * be run interactively from within an IDE.
+ */
+public class QuickStartDocTest extends AbstractJavaTest {
+
+  @Test
+  public void demonstrateSource() throws InterruptedException, ExecutionException {
+    final ActorSystem system = ActorSystem.create("QuickStart");
+
+    // #create-source
+    final Source<Integer, NotUsed> source = Source.range(1, 100);
+    // #create-source
+
+    // #run-source
+    source.runForeach(i -> System.out.println(i), system);
+    // #run-source
+
+    // #transform-source
+    final Source<BigInteger, NotUsed> factorials =
+        source.scan(BigInteger.ONE, (acc, next) -> acc.multiply(BigInteger.valueOf(next)));
+
+    final CompletionStage<IOResult> result =
+        factorials
+            .map(num -> ByteString.fromString(num.toString() + "\n"))
+            .runWith(FileIO.toPath(Paths.get("factorials.txt")), system);
+    // #transform-source
+
+    // #use-transformed-sink
+    factorials.map(BigInteger::toString).runWith(lineSink("factorial2.txt"), system);
+    // #use-transformed-sink
+
+    // #add-streams
+    factorials
+        .zipWith(Source.range(0, 99), (num, idx) -> String.format("%d! = %s", idx, num))
+        .throttle(1, Duration.ofSeconds(1))
+        // #add-streams
+        .take(2)
+        // #add-streams
+        .runForeach(s -> System.out.println(s), system);
+    // #add-streams
+
+    // #run-source-and-terminate
+    final CompletionStage<Done> done = source.runForeach(i -> System.out.println(i), system);
+
+    done.thenRun(() -> system.terminate());
+    // #run-source-and-terminate
+
+    done.toCompletableFuture().get();
+  }
+
+  // #transform-sink
+  public Sink<String, CompletionStage<IOResult>> lineSink(String filename) {
+    return Flow.of(String.class)
+        .map(s -> ByteString.fromString(s.toString() + "\n"))
+        .toMat(FileIO.toPath(Paths.get(filename)), Keep.right());
+  }
+  // #transform-sink
+
+}