Created project for gRPC task.

task05/src/main/java/de/hftstuttgart/vs/HelloClient.java

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+package de.hftstuttgart.vs;
+
+
+import io.grpc.Channel;
+import io.grpc.Grpc;
+import io.grpc.InsecureChannelCredentials;
+import io.grpc.ManagedChannel;
+import io.grpc.StatusRuntimeException;
+import java.util.concurrent.TimeUnit;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class HelloClient {
+
+    private static final Logger logger = Logger.getLogger(HelloClient.class.getName());
+
+    private final GreeterGrpc.GreeterBlockingStub blockingStub;
+
+    public HelloClient(Channel channel) {
+        blockingStub = GreeterGrpc.newBlockingStub(channel);
+    }
+
+    public void greet(String name) {
+        logger.info("Will try to greet " + name + " ...");
+        HelloRequest request = HelloRequest.newBuilder().setName(name).build();
+        HelloReply response;
+        try {
+            response = blockingStub
+                    .sayHello(request);
+        } catch (StatusRuntimeException e) {
+            logger.log(Level.WARNING, "RPC failed: {0}", e.getStatus());
+            return;
+        }
+        logger.info("Greeting: " + response.getMessage());
+    }
+
+    public static void main(String[] args) throws Exception {
+        String user = "world";
+        String target = "localhost:50051";
+
+        ManagedChannel channel = Grpc
+                .newChannelBuilder(target, InsecureChannelCredentials.create())
+                .build();
+
+        try {
+            HelloClient client = new HelloClient(channel);
+            client.greet(user);
+        } finally {
+            channel
+                    .shutdownNow()
+                    .awaitTermination(5, TimeUnit.SECONDS);
+        }
+    }
+
+}

task05/src/main/java/de/hftstuttgart/vs/HelloServer.java

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+package de.hftstuttgart.vs;
+
+import io.grpc.Grpc;
+import io.grpc.InsecureServerCredentials;
+import io.grpc.Server;
+import io.grpc.stub.StreamObserver;
+
+import java.io.IOException;
+import java.util.logging.Logger;
+import java.util.concurrent.TimeUnit;
+
+public class HelloServer {
+
+    private static final Logger logger = Logger.getLogger(HelloServer.class.getName());
+
+    private Server server;
+
+    private void start() throws IOException {
+        /* The port on which the server should run */
+        int port = 50051;
+        server = Grpc.newServerBuilderForPort(port, InsecureServerCredentials.create())
+                .addService(new GreeterImpl())
+                .build()
+                .start();
+        logger.info("Server started, listening on " + port);
+        Runtime.getRuntime().addShutdownHook(new Thread() {
+            @Override
+            public void run() {
+                // Use stderr here since the logger may have been reset by its JVM shutdown hook.
+                System.err.println("*** shutting down gRPC server since JVM is shutting down");
+                try {
+                    HelloServer.this.stop();
+                } catch (InterruptedException e) {
+                    e.printStackTrace(System.err);
+                }
+                System.err.println("*** server shut down");
+            }
+        });
+    }
+
+    private void stop() throws InterruptedException {
+        if (server != null) {
+            server.shutdown().awaitTermination(30, TimeUnit.SECONDS);
+        }
+    }
+
+    /**
+     * Await termination on the main thread since the grpc library uses daemon threads.
+     */
+    private void blockUntilShutdown() throws InterruptedException {
+        if (server != null) {
+            server.awaitTermination();
+        }
+    }
+
+    /**
+     * Main launches the server from the command line.
+     */
+    public static void main(String[] args) throws IOException, InterruptedException {
+        final HelloServer server = new HelloServer();
+        server.start();
+        server.blockUntilShutdown();
+    }
+
+    static class GreeterImpl extends GreeterGrpc.GreeterImplBase {
+
+        @Override
+        public void sayHello(HelloRequest req, StreamObserver<HelloReply> responseObserver) {
+            HelloReply reply = HelloReply.newBuilder().setMessage("Hello " + req.getName()).build();
+            responseObserver.onNext(reply);
+            responseObserver.onCompleted();
+        }
+    }
+
+}

task05/src/main/proto/helloworld.proto

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+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "de.hftstuttgart.vs";
+option java_outer_classname = "HelloWorldProto";
+option objc_class_prefix = "HLW";
+
+package helloworld;
+
+// The greeting service definition.
+service Greeter {
+  // Sends a greeting
+  rpc SayHello (HelloRequest) returns (HelloReply) {}
+}
+
+// The request message containing the user's name.
+message HelloRequest {
+  string name = 1;
+}
+
+// The response message containing the greetings
+message HelloReply {
+  string message = 1;
+}