Bugfix: Check for existence of a new transfer requires a remote-call

[demos/kafka/demos-kafka-payment-system-transfer] / src / main / java / de / juplo / kafka / payment / transfer / adapter / TransferConsumer.java

diff --git a/src/main/java/de/juplo/kafka/payment/transfer/adapter/TransferConsumer.java b/src/main/java/de/juplo/kafka/payment/transfer/adapter/TransferConsumer.java
index aa00737..920d79a 100644 (file)
--- a/src/main/java/de/juplo/kafka/payment/transfer/adapter/TransferConsumer.java
+++ b/src/main/java/de/juplo/kafka/payment/transfer/adapter/TransferConsumer.java
@@ -2,6 +2,7 @@ package de.juplo.kafka.payment.transfer.adapter;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import de.juplo.kafka.payment.transfer.domain.Transfer;
 import de.juplo.kafka.payment.transfer.ports.CreateTransferUseCase;
 import de.juplo.kafka.payment.transfer.ports.GetTransferUseCase;
 import de.juplo.kafka.payment.transfer.ports.HandleStateChangeUseCase;
@@ -191,6 +192,21 @@ public class TransferConsumer implements Runnable, ConsumerRebalanceListener
   }
 
 
+  /**
+   * Identifies the URI, at which the Group-Instance can be reached,
+   * that holds the state for a specific {@link Transfer}.
+   *
+   * The {@link Transfer#getId() ID} of the {@link Transfer} is named
+   * {@code key} here and of type {@code String}, because this example
+   * project stores the key as a String in Kafka to simplify the listing
+   * and manual manipulation of the according topic.
+   *
+   * @param key A {@code String}, that represents the {@link Transfer#getId() ID} of a {@link Transfer}.
+   * @return An {@link Optional}, that holds the URI at which the Group-Instance
+   * can be reached, that holds the state for the {@link Transfer}, that
+   * is identified by the key (if present), or is empty, if the {@link Transfer}
+   * would be handled by the local instance.
+   */
   public Optional<String> uriForKey(String key)
   {
     synchronized (this)