Further refactoring for complexity reduction

theodolite-benchmarks/uc1-application-flink/src/main/java/theodolite/uc1/application/HistoryServiceFlinkJob.java

@@ -18,29 +18,45 @@ public class HistoryServiceFlinkJob {
   private static final Logger LOGGER = LoggerFactory.getLogger(HistoryServiceFlinkJob.class);
 
   private final Configuration config = ServiceConfigurations.createWithDefaults();
+  private final StreamExecutionEnvironment env;
+  private final String applicationId;
 
-  private void run() {
+  /**
+   * Create a new instance of the {@link HistoryServiceFlinkJob}.
+   */
+  public final HistoryServiceFlinkJob() {
     final String applicationName = this.config.getString(ConfigurationKeys.APPLICATION_NAME);
     final String applicationVersion = this.config.getString(ConfigurationKeys.APPLICATION_VERSION);
-    final String applicationId = applicationName + "-" + applicationVersion;
+    this.applicationId = applicationName + "-" + applicationVersion;
+
+    this.env = StreamExecutionEnvironment.getExecutionEnvironment();
+
+    this.configureEnv();
+
+    this.buildPipeline();
+  }
+
+  private void configureEnv() {
+    final boolean checkpointing = this.config.getBoolean(ConfigurationKeys.CHECKPOINTING, true);
     final int commitIntervalMs = this.config.getInt(ConfigurationKeys.COMMIT_INTERVAL_MS);
+    if (checkpointing) {
+      this.env.enableCheckpointing(commitIntervalMs);
+    }
+  }
+
+  private void buildPipeline() {
     final String kafkaBroker = this.config.getString(ConfigurationKeys.KAFKA_BOOTSTRAP_SERVERS);
-    final String inputTopic = this.config.getString(ConfigurationKeys.KAFKA_INPUT_TOPIC);
     final String schemaRegistryUrl = this.config.getString(ConfigurationKeys.SCHEMA_REGISTRY_URL);
+    final String inputTopic = this.config.getString(ConfigurationKeys.KAFKA_INPUT_TOPIC);
     final boolean checkpointing = this.config.getBoolean(ConfigurationKeys.CHECKPOINTING, true);
 
     final KafkaConnectorFactory kafkaConnector = new KafkaConnectorFactory(
-        applicationId, kafkaBroker, checkpointing, schemaRegistryUrl);
+        this.applicationId, kafkaBroker, checkpointing, schemaRegistryUrl);
 
     final FlinkKafkaConsumer<ActivePowerRecord> kafkaConsumer =
         kafkaConnector.createConsumer(inputTopic, ActivePowerRecord.class);
 
-    final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
-    if (checkpointing) {
-      env.enableCheckpointing(commitIntervalMs);
-    }
-
-    final DataStream<ActivePowerRecord> stream = env.addSource(kafkaConsumer);
+    final DataStream<ActivePowerRecord> stream = this.env.addSource(kafkaConsumer);
 
     stream
         .rebalance()
@@ -49,9 +65,14 @@ public class HistoryServiceFlinkJob {
             + "timestamp: " + v.getTimestamp() + ", "
             + "valueInW: " + v.getValueInW() + " }")
         .print();
+  }
 
+  /**
+   * Start running this microservice.
+   */
+  public void run() {
     try {
-      env.execute(applicationId);
+      this.env.execute(this.applicationId);
     } catch (final Exception e) { // NOPMD Execution thrown by Flink
       LOGGER.error("An error occured while running this job.", e);
     }

theodolite-benchmarks/uc2-application-flink/src/main/java/theodolite/uc2/application/HistoryServiceFlinkJob.java

@@ -24,27 +24,63 @@ import titan.ccp.model.records.ActivePowerRecord;
 /**
  * The History microservice implemented as a Flink job.
  */
-public class HistoryServiceFlinkJob {
+public final class HistoryServiceFlinkJob {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(HistoryServiceFlinkJob.class);
 
   private final Configuration config = ServiceConfigurations.createWithDefaults();
+  private final StreamExecutionEnvironment env;
+  private final String applicationId;
 
-  private void run() {
+  /**
+   * Create a new instance of the {@link HistoryServiceFlinkJob}.
+   */
+  public HistoryServiceFlinkJob() {
     final String applicationName = this.config.getString(ConfigurationKeys.APPLICATION_NAME);
     final String applicationVersion = this.config.getString(ConfigurationKeys.APPLICATION_VERSION);
-    final String applicationId = applicationName + "-" + applicationVersion;
+    this.applicationId = applicationName + "-" + applicationVersion;
+
+    this.env = StreamExecutionEnvironment.getExecutionEnvironment();
+
+    this.configureEnv();
+
+    this.buildPipeline();
+  }
+
+  private void configureEnv() {
+    this.env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);
+
+    final boolean checkpointing = this.config.getBoolean(ConfigurationKeys.CHECKPOINTING, true);
     final int commitIntervalMs = this.config.getInt(ConfigurationKeys.COMMIT_INTERVAL_MS);
+    if (checkpointing) {
+      this.env.enableCheckpointing(commitIntervalMs);
+    }
+
+    // State Backend
+    final StateBackend stateBackend = StateBackends.fromConfiguration(this.config);
+    this.env.setStateBackend(stateBackend);
+
+    this.configureSerializers();
+  }
+
+  private void configureSerializers() {
+    this.env.getConfig().registerTypeWithKryoSerializer(Stats.class, new StatsSerializer());
+    this.env.getConfig().getRegisteredTypesWithKryoSerializers()
+        .forEach((c, s) -> LOGGER.info("Class " + c.getName() + " registered with serializer "
+            + s.getSerializer().getClass().getName()));
+
+  }
+
+  private void buildPipeline() {
     final String kafkaBroker = this.config.getString(ConfigurationKeys.KAFKA_BOOTSTRAP_SERVERS);
+    final String schemaRegistryUrl = this.config.getString(ConfigurationKeys.SCHEMA_REGISTRY_URL);
     final String inputTopic = this.config.getString(ConfigurationKeys.KAFKA_INPUT_TOPIC);
     final String outputTopic = this.config.getString(ConfigurationKeys.KAFKA_OUTPUT_TOPIC);
-    final String schemaRegistryUrl = this.config.getString(ConfigurationKeys.SCHEMA_REGISTRY_URL);
     final int windowDuration = this.config.getInt(ConfigurationKeys.KAFKA_WINDOW_DURATION_MINUTES);
     final boolean checkpointing = this.config.getBoolean(ConfigurationKeys.CHECKPOINTING, true);
-    final StateBackend stateBackend = StateBackends.fromConfiguration(this.config);
 
     final KafkaConnectorFactory kafkaConnector = new KafkaConnectorFactory(
-        applicationId, kafkaBroker, checkpointing, schemaRegistryUrl);
+        this.applicationId, kafkaBroker, checkpointing, schemaRegistryUrl);
 
     final FlinkKafkaConsumer<ActivePowerRecord> kafkaSource =
         kafkaConnector.createConsumer(inputTopic, ActivePowerRecord.class);
@@ -55,22 +91,7 @@ public class HistoryServiceFlinkJob {
             Serdes::String,
             Types.TUPLE(Types.STRING, Types.STRING));
 
-    final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
-
-    env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);
-    if (checkpointing) {
-      env.enableCheckpointing(commitIntervalMs);
-    }
-
-    // State Backend
-    env.setStateBackend(stateBackend);
-
-    env.getConfig().registerTypeWithKryoSerializer(Stats.class, new StatsSerializer());
-    env.getConfig().getRegisteredTypesWithKryoSerializers()
-        .forEach((c, s) -> LOGGER.info("Class " + c.getName() + " registered with serializer "
-            + s.getSerializer().getClass().getName()));
-
-    env
+    this.env
         .addSource(kafkaSource).name("[Kafka Consumer] Topic: " + inputTopic)
         .rebalance()
         .keyBy(ActivePowerRecord::getIdentifier)
@@ -83,11 +104,17 @@ public class HistoryServiceFlinkJob {
           return new Tuple2<>(key, value);
         }).name("map").returns(Types.TUPLE(Types.STRING, Types.STRING))
         .addSink(kafkaSink).name("[Kafka Producer] Topic: " + outputTopic);
+  }
+
 
-    LOGGER.info("Execution plan: {}", env.getExecutionPlan());
+  /**
+   * Start running this microservice.
+   */
+  public void run() {
+    LOGGER.info("Execution plan: {}", this.env.getExecutionPlan());
 
     try {
-      env.execute(applicationId);
+      this.env.execute(this.applicationId);
     } catch (final Exception e) { // NOPMD Execution thrown by Flink
       LOGGER.error("An error occured while running this job.", e);
     }

theodolite-benchmarks/uc4-application-flink/src/main/java/theodolite/uc4/application/AggregationServiceFlinkJob.java

@@ -38,7 +38,7 @@ import titan.ccp.model.sensorregistry.SensorRegistry;
 /**
  * The Aggregation microservice implemented as a Flink job.
  */
-public class AggregationServiceFlinkJob {
+public final class AggregationServiceFlinkJob {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(AggregationServiceFlinkJob.class);