package de.juplo.kafka.wordcount.counter;
-import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.extern.slf4j.Slf4j;
import org.apache.kafka.common.serialization.Serdes;
-import org.apache.kafka.streams.KafkaStreams;
-import org.apache.kafka.streams.KeyValue;
-import org.apache.kafka.streams.StreamsBuilder;
-import org.apache.kafka.streams.Topology;
+import org.apache.kafka.streams.*;
+import org.apache.kafka.streams.kstream.Consumed;
import org.apache.kafka.streams.kstream.KStream;
import org.apache.kafka.streams.kstream.Materialized;
import org.apache.kafka.streams.state.KeyValueBytesStoreSupplier;
-import org.apache.kafka.streams.kstream.*;
-import org.springframework.kafka.support.serializer.JsonSerde;
+import org.apache.kafka.streams.state.QueryableStoreTypes;
+import org.apache.kafka.streams.state.ReadOnlyKeyValueStore;
import java.util.Properties;
@Slf4j
public class CounterStreamProcessor
{
+ public static final String STORE_NAME = "counter";
+
+
public final KafkaStreams streams;
String inputTopic,
String outputTopic,
Properties properties,
- KeyValueBytesStoreSupplier storeSupplier,
- ObjectMapper mapper)
+ KeyValueBytesStoreSupplier storeSupplier)
{
Topology topology = CounterStreamProcessor.buildTopology(
inputTopic,
outputTopic,
- storeSupplier,
- mapper);
+ storeSupplier);
streams = new KafkaStreams(topology, properties);
}
static Topology buildTopology(
String inputTopic,
String outputTopic,
- KeyValueBytesStoreSupplier storeSupplier,
- ObjectMapper mapper)
+ KeyValueBytesStoreSupplier storeSupplier)
{
StreamsBuilder builder = new StreamsBuilder();
KStream<String, Word> source = builder.stream(
inputTopic,
- Consumed.with(
- Serdes.String(),
- new JsonSerde<>(Word.class)
- .ignoreTypeHeaders()));
+ Consumed.with(Serdes.String(), null));
source
.map((key, word) -> new KeyValue<>(word, word))
- .groupByKey(Grouped.with(
- new JsonSerde<>(Word.class)
- .forKeys()
- .noTypeInfo(),
- new JsonSerde<>(Word.class)
- .noTypeInfo()))
+ .groupByKey()
.count(Materialized.as(storeSupplier))
.toStream()
- .map((word, count) -> new KeyValue<>(word, WordCount.of(word, count)))
- .to(
- outputTopic,
- Produced.with(
- new JsonSerde<>(Word.class)
- .forKeys()
- .noTypeInfo(),
- new JsonSerde<>(WordCount.class)
- .noTypeInfo()));
+ .map((word, counter) -> new KeyValue<>(word, WordCounter.of(word, counter)))
+ .to(outputTopic);
Topology topology = builder.build();
log.info("\n\n{}", topology.describe());
return topology;
}
+ ReadOnlyKeyValueStore<Word, Long> getStore()
+ {
+ return streams.store(StoreQueryParameters.fromNameAndType(STORE_NAME, QueryableStoreTypes.keyValueStore()));
+ }
+
public void start()
{
log.info("Starting Stream-Processor");