Use Titan CC Avro Records in UC App and Workload Generator

Integrates merge requests !6 (merged) and !13 (closed).

Implements #1 (closed), #10 (closed), #16 (closed), #18 (closed), and #34 (closed).

workload-generator-commons/src/main/java/theodolite/commons/workloadgeneration/communication/kafka/KafkaRecordSender.java

@@ -2,7 +2,7 @@ package theodolite.commons.workloadgeneration.communication.kafka;
 
 import java.util.Properties;
 import java.util.function.Function;
-import kieker.common.record.IMonitoringRecord;
+import org.apache.avro.specific.SpecificRecord;
 import org.apache.kafka.clients.producer.KafkaProducer;
 import org.apache.kafka.clients.producer.Producer;
 import org.apache.kafka.clients.producer.ProducerRecord;
@@ -10,14 +10,14 @@ import org.apache.kafka.common.serialization.StringSerializer;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import theodolite.commons.workloadgeneration.functions.Transport;
-import titan.ccp.common.kieker.kafka.IMonitoringRecordSerde;
+import titan.ccp.common.kafka.avro.SchemaRegistryAvroSerdeFactory;
 
 /**
  * Sends monitoring records to Kafka.
  *
  * @param <T> {@link IMonitoringRecord} to send
  */
-public class KafkaRecordSender<T extends IMonitoringRecord> implements Transport<T> {
+public class KafkaRecordSender<T extends SpecificRecord> implements Transport<T> {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(KafkaRecordSender.class);
 
@@ -29,40 +29,74 @@ public class KafkaRecordSender<T extends IMonitoringRecord> implements Transport
 
   private final Producer<String, T> producer;
 
-  public KafkaRecordSender(final String bootstrapServers, final String topic) {
-    this(bootstrapServers, topic, x -> "", x -> null, new Properties());
-  }
-
-  public KafkaRecordSender(final String bootstrapServers, final String topic,
-      final Function<T, String> keyAccessor) {
-    this(bootstrapServers, topic, keyAccessor, x -> null, new Properties());
-  }
-
-  public KafkaRecordSender(final String bootstrapServers, final String topic,
-      final Function<T, String> keyAccessor, final Function<T, Long> timestampAccessor) {
-    this(bootstrapServers, topic, keyAccessor, timestampAccessor, new Properties());
-  }
-
   /**
    * Create a new {@link KafkaRecordSender}.
    */
-  public KafkaRecordSender(final String bootstrapServers, final String topic,
-      final Function<T, String> keyAccessor, final Function<T, Long> timestampAccessor,
-      final Properties defaultProperties) {
-    this.topic = topic;
-    this.keyAccessor = keyAccessor;
-    this.timestampAccessor = timestampAccessor;
+  private KafkaRecordSender(final Builder<T> builder) {
+    this.topic = builder.topic;
+    this.keyAccessor = builder.keyAccessor;
+    this.timestampAccessor = builder.timestampAccessor;
 
     final Properties properties = new Properties();
-    properties.putAll(defaultProperties);
-    properties.put("bootstrap.servers", bootstrapServers);
+    properties.putAll(builder.defaultProperties);
+    properties.put("bootstrap.servers", builder.bootstrapServers);
     // properties.put("acks", this.acknowledges);
     // properties.put("batch.size", this.batchSize);
     // properties.put("linger.ms", this.lingerMs);
     // properties.put("buffer.memory", this.bufferMemory);
 
+    final SchemaRegistryAvroSerdeFactory avroSerdeFactory =
+        new SchemaRegistryAvroSerdeFactory(builder.schemaRegistryUrl);
     this.producer = new KafkaProducer<>(properties, new StringSerializer(),
-        IMonitoringRecordSerde.serializer());
+        avroSerdeFactory.<T>forKeys().serializer());
+  }
+
+  /**
+   * Builder class to build a new {@link KafkaRecordSender}.
+   *
+   * @param <T> Type of the records that should later be send.
+   */
+  public static class Builder<T extends SpecificRecord> {
+
+    private final String bootstrapServers;
+    private final String topic;
+    private final String schemaRegistryUrl;
+    private Function<T, String> keyAccessor = x -> ""; // NOPMD
+    private Function<T, Long> timestampAccessor = x -> null; // NOPMD
+    private Properties defaultProperties = new Properties(); // NOPMD
+
+    /**
+     * Creates a Builder object for a {@link KafkaRecordSender}.
+     *
+     * @param bootstrapServers The Server to for accessing Kafka.
+     * @param topic The topic where to write.
+     * @param schemaRegistryUrl URL to the schema registry for avro.
+     */
+    public Builder(final String bootstrapServers, final String topic,
+        final String schemaRegistryUrl) {
+      this.bootstrapServers = bootstrapServers;
+      this.topic = topic;
+      this.schemaRegistryUrl = schemaRegistryUrl;
+    }
+
+    public Builder<T> keyAccessor(final Function<T, String> keyAccessor) {
+      this.keyAccessor = keyAccessor;
+      return this;
+    }
+
+    public Builder<T> timestampAccessor(final Function<T, Long> timestampAccessor) {
+      this.timestampAccessor = timestampAccessor;
+      return this;
+    }
+
+    public Builder<T> defaultProperties(final Properties defaultProperties) {
+      this.defaultProperties = defaultProperties;
+      return this;
+    }
+
+    public KafkaRecordSender<T> build() {
+      return new KafkaRecordSender<>(this);
+    }
   }
 
   /**