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.KStream;
+import org.apache.kafka.streams.kstream.Materialized;
import org.apache.kafka.streams.state.KeyValueBytesStoreSupplier;
-import org.apache.kafka.streams.kstream.*;
+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(), null));
+ KStream<User, Word> source = builder.stream(inputTopic);
source
.map((key, word) -> new KeyValue<>(word, word))
.groupByKey()
.count(Materialized.as(storeSupplier))
.toStream()
- .map((word, count) -> new KeyValue<>(word, WordCount.of(word, count)))
+ .map((word, counter) -> new KeyValue<>(word, WordCounter.of(word, counter)))
.to(outputTopic);
Topology topology = builder.build();
return topology;
}
+ ReadOnlyKeyValueStore<Word, Long> getStore()
+ {
+ return streams.store(StoreQueryParameters.fromNameAndType(STORE_NAME, QueryableStoreTypes.keyValueStore()));
+ }
+
public void start()
{
log.info("Starting Stream-Processor");