ActorContext.getParent for Java API #22413

akka-docs/rst/java/code/jdocs/stream/javadsl/cookbook/RecipeDigest.java

@@ -0,0 +1,129 @@
+/**
+ *  Copyright (C) 2015-2017 Lightbend Inc. <http://www.lightbend.com/>
+ */
+package jdocs.stream.javadsl.cookbook;
+
+import akka.NotUsed;
+import akka.actor.ActorSystem;
+import akka.stream.*;
+import akka.stream.javadsl.Sink;
+import akka.stream.javadsl.Source;
+import akka.stream.stage.*;
+import akka.testkit.JavaTestKit;
+import akka.util.ByteString;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
+import java.util.concurrent.TimeUnit;
+
+import static org.junit.Assert.assertEquals;
+
+public class RecipeDigest extends RecipeTest {
+  static ActorSystem system;
+  static Materializer mat;
+
+  @BeforeClass
+  public static void setup() {
+    system = ActorSystem.create("RecipeDigest");
+    mat = ActorMaterializer.create(system);
+  }
+
+  @AfterClass
+  public static void tearDown() {
+    JavaTestKit.shutdownActorSystem(system);
+    system = null;
+    mat = null;
+  }
+
+
+  //#calculating-digest
+  class DigestCalculator extends GraphStage<FlowShape<ByteString, ByteString>> {
+    private final String algorithm;
+    public Inlet<ByteString> in = Inlet.<ByteString>create("DigestCalculator.in");
+    public Outlet<ByteString> out = Outlet.<ByteString>create("DigestCalculator.out");
+    private FlowShape<ByteString, ByteString> shape = FlowShape.of(in, out);
+
+    public DigestCalculator(String algorithm) {
+      this.algorithm = algorithm;
+    }
+
+    @Override
+    public FlowShape<ByteString, ByteString> shape() {
+      return shape;
+    }
+
+    @Override
+    public GraphStageLogic createLogic(Attributes inheritedAttributes) {
+      return new GraphStageLogic(shape) {
+        final MessageDigest digest;
+
+        {
+          try {
+            digest = MessageDigest.getInstance(algorithm);
+          } catch(NoSuchAlgorithmException ex) {
+            throw new RuntimeException(ex);
+          }
+
+          setHandler(out, new AbstractOutHandler() {
+            @Override
+            public void onPull() throws Exception {
+              pull(in);
+            }
+          });
+          setHandler(in, new AbstractInHandler() {
+            @Override
+            public void onPush() throws Exception {
+              ByteString chunk = grab(in);
+              digest.update(chunk.toArray());
+              pull(in);
+            }
+
+            @Override
+            public void onUpstreamFinish() throws Exception {
+              // If the stream is finished, we need to emit the digest
+              // before completing
+              emit(out, ByteString.fromArray(digest.digest()));
+              completeStage();
+            }
+          });
+        }
+
+
+      };
+    }
+
+  }
+  //#calculating-digest
+
+  @Test
+  public void work() throws Exception {
+    new JavaTestKit(system) {
+
+      {
+        Source<ByteString, NotUsed> data = Source.from(Arrays.asList(
+          ByteString.fromString("abcdbcdecdef"),
+          ByteString.fromString("defgefghfghighijhijkijkljklmklmnlmnomnopnopq")));
+
+        //#calculating-digest2
+        final Source<ByteString, NotUsed> digest = data
+          .via(new DigestCalculator("SHA-256"));
+        //#calculating-digest2
+
+        ByteString got = digest.runWith(Sink.head(), mat).toCompletableFuture().get(3, TimeUnit.SECONDS);
+        assertEquals(ByteString.fromInts(
+          0x24, 0x8d, 0x6a, 0x61,
+          0xd2, 0x06, 0x38, 0xb8,
+          0xe5, 0xc0, 0x26, 0x93,
+          0x0c, 0x3e, 0x60, 0x39,
+          0xa3, 0x3c, 0xe4, 0x59,
+          0x64, 0xff, 0x21, 0x67,
+          0xf6, 0xec, 0xed, 0xd4,
+          0x19, 0xdb, 0x06, 0xc1), got);
+      }
+    };
+  }
+}