RoutGuide client with retry and endless stream

RouteGuideStreamingClient.java

/*
 * Copyright © 2019 Apple Inc. and the ServiceTalk project authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.servicetalk.examples.grpc.routeguide.async.streaming;

import io.servicetalk.concurrent.api.TerminalSignalConsumer;
import io.servicetalk.grpc.netty.GrpcClients;

import io.grpc.examples.routeguide.Point;
import io.grpc.examples.routeguide.RouteGuide.ClientFactory;
import io.grpc.examples.routeguide.RouteGuide.RouteGuideClient;
import io.grpc.examples.routeguide.RouteNote;

import java.time.Duration;

import static io.servicetalk.concurrent.api.Publisher.from;
import static java.time.Duration.ofSeconds;

public final class RouteGuideStreamingClient {
    public static void main(String[] args) throws Exception {
        try (RouteGuideClient client = GrpcClients.forAddress("localhost", 8081).build(new ClientFactory())) {
            client.routeChat(from(RouteNote.newBuilder()
                        .setLocation(Point.newBuilder().setLatitude(123456).setLongitude(-123456).build())
                        .setMessage("First note.").build(),
                    RouteNote.newBuilder()
                        .setLocation(Point.newBuilder().setLatitude(123456).setLongitude(-123456).build())
                        .setMessage("Querying notes.").build())
                            .repeatWhen(__ -> client.executionContext().executor().timer(ofSeconds(1)))
                            .whenOnNext(routeNote -> System.out.println("Sending note => " + routeNote))
                            .beforeOnSubscribe(__ -> System.out.println("Subscribed"))
                            .beforeRequest(value -> System.out.println("Requesting .. " + value))
                            .whenFinally(new TerminalSignalConsumer() {
                                @Override
                                public void onComplete() {
                                    System.out.println("RouteGuideStreamingClient.onComplete");
                                }

                                @Override
                                public void onError(final Throwable throwable) {
                                    System.out.println("RouteGuideStreamingClient.onError");
                                }

                                @Override
                                public void cancel() {
                                    System.out.println("RouteGuideStreamingClient.cancel");
                                }
                            }))
                    .retry((i, throwable) -> {
                        System.out.println("Retrying ... ");
                        return true;
                    })
                    .whenOnNext(System.out::println)
            // This example is demonstrating asynchronous execution, but needs to prevent the main thread from exiting
            // before the response has been processed. This isn't typical usage for an asynchronous API but is useful
            // for demonstration purposes.
                    .toFuture().get();
        }
    }
}