text: /*
   * Copyright 2015, Google Inc, Pubref Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   *
   *    * Redistributions of source code must retain the above copyright
   * notice, this list of conditions and the following disclaimer.
   *    * Redistributions in binary form must reproduce the above
   * copyright notice, this list of conditions and the following disclaimer
   * in the documentation and/or other materials provided with the
   * distribution.
   *
   *    * Neither the name of Google Inc. nor the names of its
   * contributors may be used to endorse or promote products derived from
   * this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  package org.pubref.rules_protobuf.examples.helloworld.client;
  
  import io.grpc.ManagedChannel;
  import io.grpc.ManagedChannelBuilder;
  import io.grpc.StatusRuntimeException;
  
  import java.util.concurrent.TimeUnit;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import org.pubref.rules_protobuf.examples.helloworld.GreeterGrpc;
  import org.pubref.rules_protobuf.examples.helloworld.HelloRequest;
  import org.pubref.rules_protobuf.examples.helloworld.HelloReply;
  
  /**
   * A simple client that requests a greeting from the {@link
   * HelloWorldServer}.
   */
  public class HelloWorldClient {
    private static final Logger logger = Logger.getLogger(HelloWorldClient.class.getName());
  
    private final ManagedChannel channel;
    private final GreeterGrpc.GreeterBlockingStub blockingStub;
  
    /** Construct client connecting to HelloWorld server at {@code host:port}. */
    public HelloWorldClient(String host, int port) {
      channel = ManagedChannelBuilder.forAddress(host, port)
          .usePlaintext(true)
          .build();
      blockingStub = GreeterGrpc.newBlockingStub(channel);
    }
  
    public void shutdown() throws InterruptedException {
      channel.shutdown().awaitTermination(5, TimeUnit.SECONDS);
    }
  
    /** Say hello to server. */
    public String greet(String name) {
      logger.info("Will try to greet " + name + " ...");
      HelloRequest request = HelloRequest.newBuilder().setName(name).build();
      HelloReply response;
      try {
        response = blockingStub.sayHello(request);
        logger.info("Greeting: " + response.getMessage());
        return response.getMessage();
      } catch (StatusRuntimeException e) {
        String msg = "RPC failed: " + e.getStatus();
        logger.log(Level.WARNING, msg);
        return msg;
      }
    }
  
    /**
     * Greet server. If provided, the first element of {@code args} is
     * the name to use in the greeting.
     */
    public static void main(String[] args) throws Exception {
      HelloWorldClient client = new HelloWorldClient("localhost", 50051);
      try {
        /* Access a service running on the local machine on port 50051 */
        String user = "world";
        if (args.length > 0) {
          user = args[0]; /* Use the arg as the name to greet if provided */
        }
        client.greet(user);
      } finally {
        client.shutdown();
      }
    }
  
  }
  