- Defined `JsonSerde` as default for keys and values.
- Removed the configuration of specific serdes from all steps of the
processor-topology.
- Added type-mappings for serialization/deserialization.
</parent>
<groupId>de.juplo.kafka.wordcount</groupId>
<artifactId>top10</artifactId>
- <version>1.0.3</version>
+ <version>1.1.0</version>
<name>Wordcount-Top-10</name>
<description>Top-10 stream-processor of the multi-user wordcount-example</description>
<properties>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka-streams</artifactId>
</dependency>
+ <dependency>
+ <groupId>org.springframework.kafka</groupId>
+ <artifactId>spring-kafka</artifactId>
+ </dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
package de.juplo.kafka.wordcount.top10;
-import lombok.Value;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
-@Value(staticConstructor = "of")
+@NoArgsConstructor
+@AllArgsConstructor(
+ staticName = "of",
+ access = AccessLevel.PACKAGE)
+@Data
+@JsonIgnoreProperties(ignoreUnknown = true)
public class Entry
{
- private final String word;
- private final Long count;
+ private String word;
+ private Long counter;
}
package de.juplo.kafka.wordcount.top10;
-import lombok.Getter;
-import lombok.Setter;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import lombok.*;
-@Getter
-@Setter
+@NoArgsConstructor
+@AllArgsConstructor(
+ staticName = "of",
+ access = AccessLevel.PACKAGE)
+@Data
+@JsonIgnoreProperties(ignoreUnknown = true)
public class Key
{
- private String username;
+ private String user;
private String word;
}
package de.juplo.kafka.wordcount.top10;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.*;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
-@Getter
-@Setter
+@AllArgsConstructor(access = AccessLevel.PRIVATE)
+@NoArgsConstructor
+@Data
public class Ranking
{
private Entry[] entries = new Entry[0];
- public void add(Entry newEntry)
+ public Ranking add(Entry newEntry)
{
if (entries.length == 0)
{
entries = new Entry[1];
entries[0] = newEntry;
- return;
+ return this;
}
List<Entry> list = new LinkedList<>(Arrays.asList(entries));
Entry entry;
entry = list.get(i);
- if (entry.getCount() <= newEntry.getCount())
+ if (entry.getCounter() <= newEntry.getCounter())
{
list.add(i, newEntry);
for (int j = i+1; j < list.size(); j++)
list = list.subList(0,10);
}
entries = list.toArray(num -> new Entry[num]);
- return;
+ return this;
}
}
+
+ return this;
+ }
+
+ public static Ranking of(Entry... entries)
+ {
+ return new Ranking(entries);
}
}
package de.juplo.kafka.wordcount.top10;
-import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.extern.slf4j.Slf4j;
import org.apache.kafka.clients.consumer.ConsumerConfig;
-import org.apache.kafka.common.serialization.Serdes;
import org.apache.kafka.streams.StreamsConfig;
-import org.apache.kafka.streams.state.KeyValueBytesStoreSupplier;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
+import org.springframework.kafka.support.serializer.JsonDeserializer;
+import org.springframework.kafka.support.serializer.JsonSerde;
+import org.springframework.kafka.support.serializer.JsonSerializer;
import java.util.Properties;
import java.util.concurrent.CompletableFuture;
props.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
- props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
- props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
+ props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, JsonSerde.class.getName());
+ props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, JsonSerde.class.getName());
+ props.put(JsonDeserializer.TRUSTED_PACKAGES, Top10Application.class.getPackageName());
+ props.put(JsonDeserializer.KEY_DEFAULT_TYPE, String.class.getName());
+ props.put(JsonDeserializer.VALUE_DEFAULT_TYPE, Ranking.class.getName());
+ props.put(
+ JsonDeserializer.TYPE_MAPPINGS,
+ "word:" + Key.class.getName() + "," +
+ "counter:" + Entry.class.getName());
+ props.put(JsonDeserializer.REMOVE_TYPE_INFO_HEADERS, Boolean.FALSE);
+ props.put(
+ JsonSerializer.TYPE_MAPPINGS,
+ "ranking:" + Ranking.class.getName());
props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
return props;
@Bean(initMethod = "start", destroyMethod = "stop")
public Top10StreamProcessor streamProcessor(
Top10ApplicationProperties applicationProperties,
- ObjectMapper objectMapper,
Properties streamProcessorProperties,
ConfigurableApplicationContext context)
{
Top10StreamProcessor streamProcessor = new Top10StreamProcessor(
applicationProperties.getInputTopic(),
applicationProperties.getOutputTopic(),
- objectMapper,
streamProcessorProperties);
streamProcessor.streams.setUncaughtExceptionHandler((Throwable e) ->
package de.juplo.kafka.wordcount.top10;
-import com.fasterxml.jackson.core.JsonProcessingException;
-import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.extern.slf4j.Slf4j;
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 java.util.Properties;
public Top10StreamProcessor(
String inputTopic,
String outputTopic,
- ObjectMapper mapper,
Properties props)
+ {
+ Topology topology = Top10StreamProcessor.buildTopology(
+ inputTopic,
+ outputTopic);
+
+ streams = new KafkaStreams(topology, props);
+ }
+
+ static Topology buildTopology(
+ String inputTopic,
+ String outputTopic)
{
StreamsBuilder builder = new StreamsBuilder();
builder
- .<String, String>stream(inputTopic)
- .map((keyJson, countStr) ->
- {
- try
- {
- Key key = mapper.readValue(keyJson, Key.class);
- Long count = Long.parseLong(countStr);
- Entry entry = Entry.of(key.getWord(), count);
- String entryJson = mapper.writeValueAsString(entry);
- return new KeyValue<>(key.getUsername(), entryJson);
- }
- catch (JsonProcessingException e)
- {
- throw new RuntimeException(e);
- }
- })
+ .<Key, Entry>stream(inputTopic)
+ .map((key, entry) -> new KeyValue<>(key.getUser(), entry))
.groupByKey()
.aggregate(
- () -> "{\"entries\" : []}",
- (username, entryJson, rankingJson) ->
- {
- try
- {
- Ranking ranking = mapper.readValue(rankingJson, Ranking.class);
- ranking.add(mapper.readValue(entryJson, Entry.class));
- return mapper.writeValueAsString(ranking);
- }
- catch (JsonProcessingException e)
- {
- throw new RuntimeException(e);
- }
- }
- )
+ () -> new Ranking(),
+ (user, entry, ranking) -> ranking.add(entry))
.toStream()
.to(outputTopic);
- streams = new KafkaStreams(builder.build(), props);
+ Topology topology = builder.build();
+ log.info("\n\n{}", topology.describe());
+
+ return topology;
}
public void start()
projects / demos / kafka / wordcount / commitdiff