Refactor uc1 kafka streams application

- add application name and version as a property
- checkstyle cleanups

uc1-application/src/main/java/spesb/uc1/application/ConfigurationKeys.java

@@ -5,11 +5,9 @@ package spesb.uc1.application;
  */
 public final class ConfigurationKeys {
 
-	public static final String KAFKA_BOOTSTRAP_SERVERS = "kafka.bootstrap.servers";
-
-	public static final String KAFKA_OUTPUT_TOPIC = "kafka.output.topic";
+  public static final String APPLICATION_NAME = "application.name";
 
-	public static final String KAFKA_INPUT_TOPIC = "kafka.input.topic";
+  public static final String APPLICATION_VERSION = "application.version";
 
   public static final String NUM_THREADS = "num.threads";
 
@@ -17,7 +15,11 @@ public final class ConfigurationKeys {
 
   public static final String CACHE_MAX_BYTES_BUFFERING = "cache.max.bytes.buffering";
 
-	private ConfigurationKeys() {
-	}
+  public static final String KAFKA_BOOTSTRAP_SERVERS = "kafka.bootstrap.servers";
+
+  public static final String KAFKA_INPUT_TOPIC = "kafka.input.topic";
+
+
+  private ConfigurationKeys() {}
 
 }

uc1-application/src/main/java/spesb/uc1/application/HistoryService.java

@@ -31,13 +31,17 @@ public class HistoryService {
   private void createKafkaStreamsApplication() {
 
     final KafkaStreams kafkaStreams = new KafkaStreamsBuilder()
-        .bootstrapServers(this.config.getString(ConfigurationKeys.KAFKA_BOOTSTRAP_SERVERS))
-        .inputTopic(this.config.getString(ConfigurationKeys.KAFKA_INPUT_TOPIC))
+        .applicationName(this.config.getString(ConfigurationKeys.APPLICATION_NAME))
+        .applicationVersion(this.config.getString(ConfigurationKeys.APPLICATION_VERSION))
         .numThreads(this.config.getInt(ConfigurationKeys.NUM_THREADS))
         .commitIntervalMs(this.config.getInt(ConfigurationKeys.COMMIT_INTERVAL_MS))
         .cacheMaxBytesBuffering(this.config.getInt(ConfigurationKeys.CACHE_MAX_BYTES_BUFFERING))
+        .bootstrapServers(this.config.getString(ConfigurationKeys.KAFKA_BOOTSTRAP_SERVERS))
+        .inputTopic(this.config.getString(ConfigurationKeys.KAFKA_INPUT_TOPIC))
         .build();
+
     this.stopEvent.thenRun(kafkaStreams::close);
+
     kafkaStreams.start();
   }
 

uc1-application/src/main/java/spesb/uc1/streamprocessing/KafkaStreamsBuilder.java

@@ -10,20 +10,23 @@ import titan.ccp.common.kafka.streams.PropertiesBuilder;
  * Builder for the Kafka Streams configuration.
  */
 public class KafkaStreamsBuilder {
-
-  private static final String APPLICATION_NAME = "titan-ccp-history";
-  private static final String APPLICATION_VERSION = "0.0.1";
-
   // private static final Logger LOGGER = LoggerFactory.getLogger(KafkaStreamsBuilder.class);
 
+  private String applicationName = "uc1-application"; // NOPMD
+  private String applicationVersion = "0.0.1"; // NOPMD
   private String bootstrapServers; // NOPMD
   private String inputTopic; // NOPMD
   private int numThreads = -1; // NOPMD
   private int commitIntervalMs = -1; // NOPMD
   private int cacheMaxBytesBuff = -1; // NOPMD
 
-  public KafkaStreamsBuilder inputTopic(final String inputTopic) {
-    this.inputTopic = inputTopic;
+  public KafkaStreamsBuilder applicationName(final String applicationName) {
+    this.applicationName = applicationName;
+    return this;
+  }
+
+  public KafkaStreamsBuilder applicationVersion(final String applicationVersion) {
+    this.applicationVersion = applicationVersion;
     return this;
   }
 
@@ -32,6 +35,11 @@ public class KafkaStreamsBuilder {
     return this;
   }
 
+  public KafkaStreamsBuilder inputTopic(final String inputTopic) {
+    this.inputTopic = inputTopic;
+    return this;
+  }
+
   /**
    * Sets the Kafka Streams property for the number of threads (num.stream.threads). Can be minus
    * one for using the default.
@@ -76,15 +84,13 @@ public class KafkaStreamsBuilder {
   public KafkaStreams build() {
     Objects.requireNonNull(this.inputTopic, "Input topic has not been set.");
     // TODO log parameters
-    final TopologyBuilder topologyBuilder = new TopologyBuilder(
-        this.inputTopic);
+    final TopologyBuilder topologyBuilder = new TopologyBuilder(this.inputTopic);
     final Properties properties = PropertiesBuilder
         .bootstrapServers(this.bootstrapServers)
-        .applicationId(APPLICATION_NAME + '-' + APPLICATION_VERSION) // TODO as parameter
+        .applicationId(this.applicationName + '-' + this.applicationVersion)
         .set(StreamsConfig.NUM_STREAM_THREADS_CONFIG, this.numThreads, p -> p > 0)
         .set(StreamsConfig.COMMIT_INTERVAL_MS_CONFIG, this.commitIntervalMs, p -> p >= 0)
         .set(StreamsConfig.CACHE_MAX_BYTES_BUFFERING_CONFIG, this.cacheMaxBytesBuff, p -> p >= 0)
-        // .set(StreamsConfig.METRICS_RECORDING_LEVEL_CONFIG, "DEBUG")
         .build();
     return new KafkaStreams(topologyBuilder.build(), properties);
   }

uc1-application/src/main/java/spesb/uc1/streamprocessing/TopologyBuilder.java

@@ -18,8 +18,7 @@ public class TopologyBuilder {
   private static final Logger LOGGER = LoggerFactory.getLogger(TopologyBuilder.class);
 
   private final String inputTopic;
-  private final Gson gson;
-
+  private final Gson gson = new Gson();
   private final StreamsBuilder builder = new StreamsBuilder();
 
   /**
@@ -27,14 +26,12 @@ public class TopologyBuilder {
    */
   public TopologyBuilder(final String inputTopic) {
     this.inputTopic = inputTopic;
-    this.gson = new Gson();
   }
 
   /**
    * Build the {@link Topology} for the History microservice.
    */
   public Topology build() {
-
     this.builder
         .stream(this.inputTopic, Consumed.with(
             Serdes.String(),

uc1-application/src/main/resources/META-INF/application.properties

+application.name="uc1-application"
+application.version="0.0.1"
+
 kafka.bootstrap.servers=localhost:9092
 kafka.input.topic=input
 kafka.output.topic=output
+
 num.threads=1
 commit.interval.ms=100
 cache.max.bytes.buffering=-1