Java Code Examples for org.apache.samza.application.descriptors.StreamApplicationDescriptor#getOutputStream()

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  KafkaSystemDescriptor trackingSystem = new KafkaSystemDescriptor("tracking");

  KafkaInputDescriptor<PageViewEvent> inputStreamDescriptor =
      trackingSystem.getInputDescriptor("pageViewEvent", new JsonSerdeV2<>(PageViewEvent.class));

  KafkaOutputDescriptor<KV<String, StatsOutput>> outputStreamDescriptor =
      trackingSystem.getOutputDescriptor("pageViewEventPerMember",
          KVSerde.of(new StringSerde(), new JsonSerdeV2<>(StatsOutput.class)));

  appDescriptor.withDefaultSystem(trackingSystem);
  MessageStream<PageViewEvent> pageViewEvents = appDescriptor.getInputStream(inputStreamDescriptor);
  OutputStream<KV<String, StatsOutput>> pageViewEventPerMember = appDescriptor.getOutputStream(outputStreamDescriptor);

  pageViewEvents
      .partitionBy(pve -> pve.getMemberId(), pve -> pve,
          KVSerde.of(new StringSerde(), new JsonSerdeV2<>(PageViewEvent.class)), "partitionBy")
      .map(KV::getValue)
      .flatMap(new MyStatsCounter())
      .map(stats -> KV.of(stats.memberId, stats))
      .sendTo(pageViewEventPerMember);
}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  KafkaSystemDescriptor trackingSystem = new KafkaSystemDescriptor("tracking");

  KafkaInputDescriptor<PageViewEvent> inputStreamDescriptor =
      trackingSystem.getInputDescriptor("pageViewEvent", new JsonSerdeV2<>(PageViewEvent.class));

  KafkaOutputDescriptor<KV<String, PageViewCount>> outputStreamDescriptor =
      trackingSystem.getOutputDescriptor("pageViewEventPerMember",
          KVSerde.of(new StringSerde(), new JsonSerdeV2<>(PageViewCount.class)));

  MessageStream<PageViewEvent> pageViewEvents = appDescriptor.getInputStream(inputStreamDescriptor);
  OutputStream<KV<String, PageViewCount>> pageViewEventPerMemberStream = appDescriptor.getOutputStream(outputStreamDescriptor);

  SupplierFunction<Integer> initialValue = () -> 0;
  FoldLeftFunction<PageViewEvent, Integer> foldLeftFn = (m, c) -> c + 1;
  pageViewEvents
      .window(Windows.keyedTumblingWindow(PageViewEvent::getMemberId, Duration.ofSeconds(10), initialValue, foldLeftFn, null, null)
          .setEarlyTrigger(Triggers.repeat(Triggers.count(5)))
          .setAccumulationMode(AccumulationMode.DISCARDING), "tumblingWindow")
      .map(windowPane -> KV.of(windowPane.getKey().getKey(), buildPageViewCount(windowPane)))
      .sendTo(pageViewEventPerMemberStream);
}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  KafkaSystemDescriptor trackingSystem = new KafkaSystemDescriptor("tracking");

  KafkaInputDescriptor<PageViewEvent> inputStreamDescriptor =
      trackingSystem.getInputDescriptor("pageViewEvent", new JsonSerdeV2<>(PageViewEvent.class));
  KafkaOutputDescriptor<Integer> outputStreamDescriptor =
      trackingSystem.getOutputDescriptor("pageViewEventPerMember", new IntegerSerde());

  SupplierFunction<Integer> initialValue = () -> 0;
  FoldLeftFunction<PageViewEvent, Integer> counter = (m, c) -> c == null ? 1 : c + 1;
  MessageStream<PageViewEvent> inputStream = appDescriptor.getInputStream(inputStreamDescriptor);
  OutputStream<Integer> outputStream = appDescriptor.getOutputStream(outputStreamDescriptor);

  // create a tumbling window that outputs the number of message collected every 10 minutes.
  // also emit early results if either the number of messages collected reaches 30000, or if no new messages arrive
  // for 1 minute.
  inputStream
      .window(Windows.tumblingWindow(Duration.ofMinutes(10), initialValue, counter, new IntegerSerde())
          .setLateTrigger(Triggers.any(Triggers.count(30000),
              Triggers.timeSinceLastMessage(Duration.ofMinutes(1)))), "window")
      .map(WindowPane::getMessage)
      .sendTo(outputStream);
}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  KafkaSystemDescriptor trackingSystem = new KafkaSystemDescriptor("tracking");

  KafkaInputDescriptor<AdClickEvent> inputStreamDescriptor =
      trackingSystem.getInputDescriptor("adClickEvent", new JsonSerdeV2<>(AdClickEvent.class));

  KafkaOutputDescriptor<KV<String, EnrichedAdClickEvent>> outputStreamDescriptor =
      trackingSystem.getOutputDescriptor("enrichedAdClickEvent",
          KVSerde.of(new StringSerde(), new JsonSerdeV2<>(EnrichedAdClickEvent.class)));

  MessageStream<AdClickEvent> adClickEventStream = appDescriptor.getInputStream(inputStreamDescriptor);
  OutputStream<KV<String, EnrichedAdClickEvent>> enrichedAdClickStream =
      appDescriptor.getOutputStream(outputStreamDescriptor);

  adClickEventStream
      .flatMapAsync(AsyncApplicationExample::enrichAdClickEvent)
      .map(enrichedAdClickEvent -> KV.of(enrichedAdClickEvent.getCountry(), enrichedAdClickEvent))
      .sendTo(enrichedAdClickStream);
}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  JsonSerdeV2<PageView> inputSerde = new JsonSerdeV2<>(PageView.class);
  KVSerde<String, Integer> outputSerde = KVSerde.of(new StringSerde(), new IntegerSerde());
  KafkaSystemDescriptor ksd = new KafkaSystemDescriptor(SYSTEM);
  KafkaInputDescriptor<PageView> id = ksd.getInputDescriptor(INPUT_TOPIC, inputSerde);
  KafkaOutputDescriptor<KV<String, Integer>> od = ksd.getOutputDescriptor(OUTPUT_TOPIC, outputSerde);

  MessageStream<PageView> pageViews = appDescriptor.getInputStream(id);
  OutputStream<KV<String, Integer>> outputStream = appDescriptor.getOutputStream(od);

  pageViews
      .filter(m -> !FILTER_KEY.equals(m.getUserId()))
      .window(Windows.keyedSessionWindow(PageView::getUserId, Duration.ofSeconds(3),
          new StringSerde(), new JsonSerdeV2<>(PageView.class)), "sessionWindow")
      .map(m -> KV.of(m.getKey().getKey(), m.getMessage().size()))
      .sendTo(outputStream);
}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  JsonSerdeV2<PageView> inputSerde = new JsonSerdeV2<>(PageView.class);
  KVSerde<String, Integer> outputSerde = KVSerde.of(new StringSerde(), new IntegerSerde());
  KafkaSystemDescriptor ksd = new KafkaSystemDescriptor(SYSTEM);
  KafkaInputDescriptor<PageView> id = ksd.getInputDescriptor(INPUT_TOPIC, inputSerde);
  KafkaOutputDescriptor<KV<String, Integer>> od = ksd.getOutputDescriptor(OUTPUT_TOPIC, outputSerde);

  MessageStream<PageView> pageViews = appDescriptor.getInputStream(id);
  OutputStream<KV<String, Integer>> outputStream = appDescriptor.getOutputStream(od);

  pageViews
      .filter(m -> !FILTER_KEY.equals(m.getUserId()))
      .window(Windows.keyedTumblingWindow(PageView::getUserId, Duration.ofSeconds(3),
          new StringSerde(), new JsonSerdeV2<>(PageView.class)), "tumblingWindow")
      .map(m -> KV.of(m.getKey().getKey(), m.getMessage().size()))
      .sendTo(outputStream);

}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  Config config = appDescriptor.getConfig();
  KafkaSystemDescriptor kafkaSystemDescriptor = new KafkaSystemDescriptor(TEST_SYSTEM);
  KafkaOutputDescriptor<PageView>
      outputDescriptor = kafkaSystemDescriptor.getOutputDescriptor(NON_GUEST_PAGE_VIEW_STREAM, new NoOpSerde<>());
  OutputStream<PageView> nonGuestPageViewStream = appDescriptor.getOutputStream(outputDescriptor);

  Predicate<PageView> failProcess = (Predicate<PageView> & Serializable) (ignored) -> config.getBoolean(FAIL_PROCESS, false);
  Predicate<PageView> failDownstreamOperator = (Predicate<PageView> & Serializable) (ignored) -> config.getBoolean(FAIL_DOWNSTREAM_OPERATOR, false);
  Supplier<Long> processJitter = (Supplier<Long> & Serializable) () -> config.getLong(PROCESS_JITTER, 100);

  appDescriptor.getInputStream(kafkaSystemDescriptor.getInputDescriptor(PAGE_VIEW_STREAM, new NoOpSerde<PageView>()))
      .flatMapAsync(pageView -> filterGuestPageViews(pageView, failProcess, processJitter))
      .filter(pageView -> filterLoginPageViews(pageView, failDownstreamOperator))
      .sendTo(nonGuestPageViewStream);
}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  KafkaSystemDescriptor trackingSystem = new KafkaSystemDescriptor("tracking");

  KafkaInputDescriptor<PageViewEvent> inputStreamDescriptor =
      trackingSystem.getInputDescriptor("pageViewEvent", new JsonSerdeV2<>(PageViewEvent.class));

  KafkaOutputDescriptor<KV<String, MyStreamOutput>> outputStreamDescriptor =
      trackingSystem.getOutputDescriptor("pageViewEventPerMember",
          KVSerde.of(new StringSerde(), new JsonSerdeV2<>(MyStreamOutput.class)));

  appDescriptor.withDefaultSystem(trackingSystem);
  MessageStream<PageViewEvent> pageViewEvents = appDescriptor.getInputStream(inputStreamDescriptor);
  OutputStream<KV<String, MyStreamOutput>> pageViewEventPerMember = appDescriptor.getOutputStream(outputStreamDescriptor);

  pageViewEvents
      .partitionBy(pve -> pve.getMemberId(), pve -> pve,
          KVSerde.of(new StringSerde(), new JsonSerdeV2<>(PageViewEvent.class)), "partitionBy")
      .window(Windows.keyedTumblingWindow(
          KV::getKey, Duration.ofMinutes(5), () -> 0, (m, c) -> c + 1, null, null), "window")
      .map(windowPane -> KV.of(windowPane.getKey().getKey(), new MyStreamOutput(windowPane)))
      .sendTo(pageViewEventPerMember);
}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  KafkaSystemDescriptor kafkaSystemDescriptor = new KafkaSystemDescriptor(KAFKA_SYSTEM_NAME)
      .withConsumerZkConnect(KAFKA_CONSUMER_ZK_CONNECT)
      .withProducerBootstrapServers(KAFKA_PRODUCER_BOOTSTRAP_SERVERS)
      .withDefaultStreamConfigs(KAFKA_DEFAULT_STREAM_CONFIGS);

  KVSerde<String, PageView> serde = KVSerde.of(new StringSerde(), new JsonSerdeV2<>(PageView.class));
  KafkaInputDescriptor<KV<String, PageView>> inputDescriptor =
      kafkaSystemDescriptor.getInputDescriptor(INPUT_STREAM_ID, serde);
  KafkaOutputDescriptor<KV<String, PageView>> outputDescriptor =
      kafkaSystemDescriptor.getOutputDescriptor(OUTPUT_STREAM_ID, serde);

  appDescriptor.withDefaultSystem(kafkaSystemDescriptor);

  MessageStream<KV<String, PageView>> pageViews = appDescriptor.getInputStream(inputDescriptor);
  OutputStream<KV<String, PageView>> filteredPageViews = appDescriptor.getOutputStream(outputDescriptor);

  pageViews
      .filter(kv -> !INVALID_USER_ID.equals(kv.value.userId))
      .sendTo(filteredPageViews);
}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  // Define a system descriptor for Kafka
  KafkaSystemDescriptor kafkaSystemDescriptor =
      new KafkaSystemDescriptor("kafka").withConsumerZkConnect(KAFKA_CONSUMER_ZK_CONNECT)
          .withProducerBootstrapServers(KAFKA_PRODUCER_BOOTSTRAP_SERVERS)
          .withDefaultStreamConfigs(KAFKA_DEFAULT_STREAM_CONFIGS);

  KafkaInputDescriptor<PageView> pageViewInputDescriptor =
      kafkaSystemDescriptor.getInputDescriptor(INPUT_PAGEVIEW_STREAM_ID, new JsonSerdeV2<>(PageView.class));

  // Define a system descriptor for Azure Blob Storage
  GenericSystemDescriptor azureBlobSystemDescriptor =
      new GenericSystemDescriptor(OUTPUT_SYSTEM, "org.apache.samza.system.azureblob.AzureBlobSystemFactory");

  GenericOutputDescriptor<PageViewAvroRecord> azureBlobOuputDescriptor =
      azureBlobSystemDescriptor.getOutputDescriptor(OUTPUT_STREAM, new NoOpSerde<>());

  // Set Kafka as the default system for the job
  appDescriptor.withDefaultSystem(kafkaSystemDescriptor);

  // Define the input and output streams with descriptors
  MessageStream<PageView> pageViewInput = appDescriptor.getInputStream(pageViewInputDescriptor);
  OutputStream<PageViewAvroRecord> pageViewAvroRecordOutputStream = appDescriptor.getOutputStream(azureBlobOuputDescriptor);

  // Define the execution flow with the high-level API
  pageViewInput
      .map((message) -> {
        LOG.info("Sending: Received PageViewEvent with pageId: " + message.pageId);
        return PageViewAvroRecord.buildPageViewRecord(message);
      })
      .sendTo(pageViewAvroRecordOutputStream);
}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  // Define your system here
  EventHubsSystemDescriptor systemDescriptor = new EventHubsSystemDescriptor("eventhubs");

  // Choose your serializer/deserializer for the EventData payload
  StringSerde serde = new StringSerde();

  // Define the input and output descriptors with respective configs
  EventHubsInputDescriptor<KV<String, String>> inputDescriptor =
      systemDescriptor.getInputDescriptor(INPUT_STREAM_ID, EVENTHUBS_NAMESPACE, EVENTHUBS_INPUT_ENTITY, serde)
          .withSasKeyName(appDescriptor.getConfig().get(EVENTHUBS_SAS_KEY_NAME_CONFIG))
          .withSasKey(appDescriptor.getConfig().get(EVENTHUBS_SAS_KEY_TOKEN_CONFIG));

  EventHubsOutputDescriptor<KV<String, String>> outputDescriptor =
      systemDescriptor.getOutputDescriptor(OUTPUT_STREAM_ID, EVENTHUBS_NAMESPACE, EVENTHUBS_OUTPUT_ENTITY, serde)
          .withSasKeyName(appDescriptor.getConfig().get(EVENTHUBS_SAS_KEY_NAME_CONFIG))
          .withSasKey(appDescriptor.getConfig().get(EVENTHUBS_SAS_KEY_TOKEN_CONFIG));

  // Define the input and output streams with descriptors
  MessageStream<KV<String, String>> eventhubInput = appDescriptor.getInputStream(inputDescriptor);
  OutputStream<KV<String, String>> eventhubOutput = appDescriptor.getOutputStream(outputDescriptor);

  // Define the execution flow with the high-level API
  eventhubInput
      .map((message) -> {
        System.out.println("Sending: ");
        System.out.println("Received Key: " + message.getKey());
        System.out.println("Received Message: " + message.getValue());
        return message;
      })
      .sendTo(eventhubOutput);
}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  Serde<Profile> profileSerde = new JsonSerdeV2<>(Profile.class);
  Serde<PageView> pageViewSerde = new JsonSerdeV2<>(PageView.class);
  Serde<EnrichedPageView> joinResultSerde = new JsonSerdeV2<>(EnrichedPageView.class);

  KafkaSystemDescriptor kafkaSystemDescriptor = new KafkaSystemDescriptor(KAFKA_SYSTEM_NAME)
      .withConsumerZkConnect(KAFKA_CONSUMER_ZK_CONNECT)
      .withProducerBootstrapServers(KAFKA_PRODUCER_BOOTSTRAP_SERVERS)
      .withDefaultStreamConfigs(KAFKA_DEFAULT_STREAM_CONFIGS);

  KafkaInputDescriptor<Profile> profileInputDescriptor =
      kafkaSystemDescriptor.getInputDescriptor(PROFILE_STREAM_ID, profileSerde);
  KafkaInputDescriptor<PageView> pageViewInputDescriptor =
      kafkaSystemDescriptor.getInputDescriptor(PAGEVIEW_STREAM_ID, pageViewSerde);
  KafkaOutputDescriptor<EnrichedPageView> joinResultOutputDescriptor =
      kafkaSystemDescriptor.getOutputDescriptor(OUTPUT_TOPIC, joinResultSerde);

  RocksDbTableDescriptor<String, Profile> profileTableDescriptor =
      new RocksDbTableDescriptor<String, Profile>("profile-table", KVSerde.of(new StringSerde(), profileSerde));

  appDescriptor.withDefaultSystem(kafkaSystemDescriptor);

  MessageStream<Profile> profileStream = appDescriptor.getInputStream(profileInputDescriptor);
  MessageStream<PageView> pageViewStream = appDescriptor.getInputStream(pageViewInputDescriptor);
  OutputStream<EnrichedPageView> joinResultStream = appDescriptor.getOutputStream(joinResultOutputDescriptor);
  Table<KV<String, Profile>> profileTable = appDescriptor.getTable(profileTableDescriptor);

  profileStream
      .map(profile -> KV.of(profile.userId, profile))
      .sendTo(profileTable);

  pageViewStream
      .partitionBy(pv -> pv.userId, pv -> pv, KVSerde.of(new StringSerde(), pageViewSerde), "join")
      .join(profileTable, new JoinFn())
      .sendTo(joinResultStream);
}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  KafkaSystemDescriptor kafkaSystemDescriptor = new KafkaSystemDescriptor(KAFKA_SYSTEM_NAME)
      .withConsumerZkConnect(KAFKA_CONSUMER_ZK_CONNECT)
      .withProducerBootstrapServers(KAFKA_PRODUCER_BOOTSTRAP_SERVERS)
      .withDefaultStreamConfigs(KAFKA_DEFAULT_STREAM_CONFIGS);

  KafkaInputDescriptor<String> stockSymbolInputDescriptor =
      kafkaSystemDescriptor.getInputDescriptor(INPUT_STREAM_ID, new StringSerde());
  KafkaOutputDescriptor<StockPrice> stockPriceOutputDescriptor =
      kafkaSystemDescriptor.getOutputDescriptor(OUTPUT_STREAM_ID, new JsonSerdeV2<>(StockPrice.class));
  appDescriptor.withDefaultSystem(kafkaSystemDescriptor);
  MessageStream<String> stockSymbolStream = appDescriptor.getInputStream(stockSymbolInputDescriptor);
  OutputStream<StockPrice> stockPriceStream = appDescriptor.getOutputStream(stockPriceOutputDescriptor);

  RemoteTableDescriptor<String, Double> remoteTableDescriptor =
      new RemoteTableDescriptor("remote-table")
          .withReadRateLimit(10)
          .withReadFunction(new StockPriceReadFunction());
  CachingTableDescriptor<String, Double> cachedRemoteTableDescriptor =
      new CachingTableDescriptor<>("cached-remote-table", remoteTableDescriptor)
          .withReadTtl(Duration.ofSeconds(5));
  Table<KV<String, Double>> cachedRemoteTable = appDescriptor.getTable(cachedRemoteTableDescriptor);

  stockSymbolStream
      .map(symbol -> new KV<String, Void>(symbol, null))
      .join(cachedRemoteTable, new JoinFn())
      .sendTo(stockPriceStream);

}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  Table<KV<Integer, TestTableData.Profile>> table = appDescriptor.getTable(
      new RocksDbTableDescriptor<Integer, TestTableData.Profile>("profile-view-store",
          KVSerde.of(new IntegerSerde(), new TestTableData.ProfileJsonSerde())));

  KafkaSystemDescriptor ksd = new KafkaSystemDescriptor("test");

  KafkaInputDescriptor<KV<String, TestTableData.Profile>> profileISD =
      ksd.getInputDescriptor("Profile", KVSerde.of(new StringSerde(), new JsonSerdeV2<>()));

  KafkaInputDescriptor<KV<String, TestTableData.PageView>> pageViewISD =
      ksd.getInputDescriptor("PageView", KVSerde.of(new StringSerde(), new JsonSerdeV2<>()));
  KafkaOutputDescriptor<TestTableData.EnrichedPageView> enrichedPageViewOSD =
      ksd.getOutputDescriptor("EnrichedPageView", new JsonSerdeV2<>());

  appDescriptor.getInputStream(profileISD)
      .map(m -> new KV(m.getValue().getMemberId(), m.getValue()))
      .sendTo(table)
      .sink((kv, collector, coordinator) -> {
        LOG.info("Inserted Profile with Key: {} in profile-view-store", kv.getKey());
      });

  OutputStream<TestTableData.EnrichedPageView> outputStream = appDescriptor.getOutputStream(enrichedPageViewOSD);
  appDescriptor.getInputStream(pageViewISD)
      .partitionBy(pv -> pv.getValue().getMemberId(),  pv -> pv.getValue(), KVSerde.of(new IntegerSerde(), new JsonSerdeV2<>(TestTableData.PageView.class)), "p1")
      .join(table, new PageViewToProfileJoinFunction())
      .sendTo(outputStream)
      .map(TestTableData.EnrichedPageView::getPageKey)
      .sink((joinPageKey, collector, coordinator) -> {
        collector.send(new OutgoingMessageEnvelope(new SystemStream("test", "JoinPageKeys"), null, null, joinPageKey));
      });

}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
  KafkaSystemDescriptor ksd = new KafkaSystemDescriptor(systemName);
  KafkaOutputDescriptor<String> osd = ksd.getOutputDescriptor(outputTopic, new StringSerde());
  OutputStream<String> outputStream = appDescriptor.getOutputStream(osd);

  for (String inputTopic : inputTopics) {
    KafkaInputDescriptor<String> isd = ksd.getInputDescriptor(inputTopic, new NoOpSerde<>());
    MessageStream<String> inputStream = appDescriptor.getInputStream(isd);
    inputStream.map(new TestMapFunction(appName, processorName)).sendTo(outputStream);
  }
}
 

@Override
public void describe(StreamApplicationDescriptor app) {

  KafkaSystemDescriptor kafkaSystemDescriptor = new KafkaSystemDescriptor(KAFKA_SYSTEM_NAME)
      .withConsumerZkConnect(KAFKA_CONSUMER_ZK_CONNECT)
      .withProducerBootstrapServers(KAFKA_PRODUCER_BOOTSTRAP_SERVERS)
      .withDefaultStreamConfigs(KAFKA_DEFAULT_STREAM_CONFIGS);

  KafkaInputDescriptor<String> wordInputDescriptor =
      kafkaSystemDescriptor.getInputDescriptor(INPUT_STREAM_ID, new StringSerde());

  KafkaOutputDescriptor<String> countOutputDescriptor =
      kafkaSystemDescriptor.getOutputDescriptor(OUTPUT_STREAM_ID, new StringSerde());

  MyCouchbaseTableWriteFunction writeFn = new MyCouchbaseTableWriteFunction(BUCKET_NAME, CLUSTER_NODES)
      .withBootstrapCarrierDirectPort(COUCHBASE_PORT)
      .withUsernameAndPassword(BUCKET_NAME, BUCKET_PASSWORD)
      .withTimeout(Duration.ofSeconds(5));

  TableRetryPolicy retryPolicy = new TableRetryPolicy()
      .withFixedBackoff(Duration.ofSeconds(1))
      .withStopAfterAttempts(3);

  RemoteTableDescriptor couchbaseTableDescriptor = new RemoteTableDescriptor("couchbase-table")
      .withReadFunction(new NoOpTableReadFunction())
      .withReadRateLimiterDisabled()
      .withWriteFunction(writeFn)
      .withWriteRetryPolicy(retryPolicy)
      .withWriteRateLimit(4);

  app.withDefaultSystem(kafkaSystemDescriptor);
  MessageStream<String> wordStream = app.getInputStream(wordInputDescriptor);
  OutputStream<String> countStream = app.getOutputStream(countOutputDescriptor);
  app.getTable(couchbaseTableDescriptor);

  wordStream
      .flatMap(m -> Arrays.asList(m.split(" ")))
      .filter(word -> word != null && word.length() > 0)
      .map(new MyCountFunction())
      .map(countString -> currentTime() + " " + countString)
      .sendTo(countStream);
}
 

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {

  Duration windowDuration =
      appDescriptor.getConfig().containsKey("deploy.test") ? Duration.ofMillis(10) : Duration.ofSeconds(10);
  // Define a SystemDescriptor for Wikipedia data
  WikipediaSystemDescriptor wikipediaSystemDescriptor = new WikipediaSystemDescriptor("irc.wikimedia.org", 6667);

  // Define InputDescriptors for consuming wikipedia data
  WikipediaInputDescriptor wikipediaInputDescriptor = wikipediaSystemDescriptor
      .getInputDescriptor("en-wikipedia")
      .withChannel(WIKIPEDIA_CHANNEL);
  WikipediaInputDescriptor wiktionaryInputDescriptor = wikipediaSystemDescriptor
      .getInputDescriptor("en-wiktionary")
      .withChannel(WIKTIONARY_CHANNEL);
  WikipediaInputDescriptor wikiNewsInputDescriptor = wikipediaSystemDescriptor
      .getInputDescriptor("en-wikinews")
      .withChannel(WIKINEWS_CHANNEL);

  // Define a system descriptor for Kafka
  KafkaSystemDescriptor kafkaSystemDescriptor = new KafkaSystemDescriptor("kafka")
      .withConsumerZkConnect(KAFKA_CONSUMER_ZK_CONNECT)
      .withProducerBootstrapServers(KAFKA_PRODUCER_BOOTSTRAP_SERVERS)
      .withDefaultStreamConfigs(KAFKA_DEFAULT_STREAM_CONFIGS);

  // Define an output descriptor
  KafkaOutputDescriptor<WikipediaStatsOutput> statsOutputDescriptor =
      kafkaSystemDescriptor.getOutputDescriptor("wikipedia-stats", new JsonSerdeV2<>(WikipediaStatsOutput.class));


  // Set the default system descriptor to Kafka, so that it is used for all
  // internal resources, e.g., kafka topic for checkpointing, coordinator stream.
  appDescriptor.withDefaultSystem(kafkaSystemDescriptor);
  MessageStream<WikipediaFeedEvent> wikipediaEvents = appDescriptor.getInputStream(wikipediaInputDescriptor);
  MessageStream<WikipediaFeedEvent> wiktionaryEvents = appDescriptor.getInputStream(wiktionaryInputDescriptor);
  MessageStream<WikipediaFeedEvent> wikiNewsEvents = appDescriptor.getInputStream(wikiNewsInputDescriptor);
  OutputStream<WikipediaStatsOutput> wikipediaStats = appDescriptor.getOutputStream(statsOutputDescriptor);

  // Merge inputs
  MessageStream<WikipediaFeedEvent> allWikipediaEvents =
      MessageStream.mergeAll(ImmutableList.of(wikipediaEvents, wiktionaryEvents, wikiNewsEvents));


  // Parse, update stats, prepare output, and send
  allWikipediaEvents
      .map(WikipediaParser::parseEvent)
      .window(Windows.tumblingWindow(windowDuration,
          WikipediaStats::new, new WikipediaStatsAggregator(), WikipediaStats.serde()), "statsWindow")
      .map(this::formatOutput)
      .sendTo(wikipediaStats);
}