Java Code Examples for org.apache.kafka.streams.kstream.KStream#flatMapValues()

The following examples show how to use org.apache.kafka.streams.kstream.KStream#flatMapValues() . You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example 1
Source File: StreamingWordCount.java    From Kafka-Streams-Real-time-Stream-Processing with The Unlicense 7 votes vote down vote up 
public static void main(final String[] args) {
    final Properties props = new Properties();
    props.put(StreamsConfig.APPLICATION_ID_CONFIG, "StreamingWordCount");
    props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
    props.put(StreamsConfig.STATE_DIR_CONFIG, "state-store");
    props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
    props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());

    logger.info("Start Reading Messages");
    StreamsBuilder streamBuilder = new StreamsBuilder();
    KStream<String, String> KS0 = streamBuilder.stream("streaming-word-count");

    KStream<String, String> KS1 = KS0.flatMapValues(value ->
        Arrays.asList(value.toLowerCase().split(" ")));

    KGroupedStream<String, String> KGS2 = KS1.groupBy((key, value) -> value);

    KTable<String, Long> KTS3 = KGS2.count();

    KTS3.toStream().peek(
        (k, v) -> logger.info("Key = " + k + " Value = " + v.toString())
    );

    KafkaStreams streams = new KafkaStreams(streamBuilder.build(), props);
    streams.start();
    Runtime.getRuntime().addShutdownHook(new Thread(streams::close));
}
Example 2
Source File: EventSourcedStreams.java    From simplesource with Apache License 2.0 5 votes vote down vote up 
static <K, A> KStream<K, AggregateUpdate<A>> getAggregateUpdates(final KStream<K, AggregateUpdateResult<A>> aggregateUpdateStream) {
    return aggregateUpdateStream
            .flatMapValues(update -> update.updatedAggregateResult().fold(
                    reasons -> Collections.emptyList(),
                    Collections::singletonList
            ));
}
Example 3
Source File: EventSourcedStreams.java    From simplesource with Apache License 2.0 4 votes vote down vote up 
static <K, E, A> KStream<K, ValueWithSequence<E>> getEventsWithSequence(final KStream<K, CommandEvents<E, A>> eventResultStream) {
    return eventResultStream.flatMapValues(result -> result.eventValue()
            .fold(reasons -> Collections.emptyList(), ArrayList::new));
}