query: 1.0.6 - Refined `QueryStreamProcessor`

[demos/kafka/wordcount] / src / main / java / de / juplo / kafka / wordcount / query / QueryStreamProcessor.java

diff --git a/src/main/java/de/juplo/kafka/wordcount/query/QueryStreamProcessor.java b/src/main/java/de/juplo/kafka/wordcount/query/QueryStreamProcessor.java
index 2d3d4c8..efa28ca 100644 (file)
--- a/src/main/java/de/juplo/kafka/wordcount/query/QueryStreamProcessor.java
+++ b/src/main/java/de/juplo/kafka/wordcount/query/QueryStreamProcessor.java
@@ -6,10 +6,7 @@ import jakarta.annotation.PostConstruct;
 import jakarta.annotation.PreDestroy;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.kafka.common.serialization.Serdes;
-import org.apache.kafka.streams.KafkaStreams;
-import org.apache.kafka.streams.KeyQueryMetadata;
-import org.apache.kafka.streams.StoreQueryParameters;
-import org.apache.kafka.streams.StreamsBuilder;
+import org.apache.kafka.streams.*;
 import org.apache.kafka.streams.kstream.KStream;
 import org.apache.kafka.streams.kstream.KTable;
 import org.apache.kafka.streams.kstream.Materialized;
@@ -25,9 +22,10 @@ import java.util.Properties;
 @Slf4j
 public class QueryStreamProcessor
 {
+       public static final String STORE_NAME = "rankings-by-username";
+
        public final KafkaStreams streams;
        public final HostInfo hostInfo;
-       public final String storeName = "rankingsByUsername";
        public final StoreQueryParameters<ReadOnlyKeyValueStore<String, String>> storeParameters;
        public final ObjectMapper mapper;
 
@@ -38,6 +36,18 @@ public class QueryStreamProcessor
                        String usersInputTopic,
                        String rankingInputTopic,
                        ObjectMapper mapper)
+       {
+               Topology topology = buildTopology(usersInputTopic, rankingInputTopic, mapper);
+               streams = new KafkaStreams(topology, props);
+               hostInfo = applicationServer;
+               storeParameters = StoreQueryParameters.fromNameAndType(STORE_NAME, QueryableStoreTypes.keyValueStore());;
+               this.mapper = mapper;
+       }
+
+       static Topology buildTopology(
+                       String usersInputTopic,
+                       String rankingInputTopic,
+                       ObjectMapper mapper)
        {
                StreamsBuilder builder = new StreamsBuilder();
 
@@ -63,17 +73,17 @@ public class QueryStreamProcessor
                                                throw new RuntimeException(e);
                                        }
                                })
-                               .toTable(Materialized.as(storeName));
+                               .toTable(Materialized.as(STORE_NAME));
 
-               streams = new KafkaStreams(builder.build(), props);
-               hostInfo = applicationServer;
-               storeParameters = StoreQueryParameters.fromNameAndType(storeName, QueryableStoreTypes.keyValueStore());;
-               this.mapper = mapper;
+               Topology topology = builder.build();
+               log.info("\n\n{}", topology.describe());
+
+               return topology;
        }
 
        public Optional<URI> getRedirect(String username)
        {
-               KeyQueryMetadata metadata = streams.queryMetadataForKey(storeName, username, Serdes.String().serializer());
+               KeyQueryMetadata metadata = streams.queryMetadataForKey(STORE_NAME, username, Serdes.String().serializer());
                HostInfo activeHost = metadata.activeHost();
                log.debug("Local store for {}: {}, {}:{}", username, metadata.partition(), activeHost.host(), activeHost.port());