Automatically rebuild the state after a crash / restart

[demos/kafka/demos-kafka-payment-system-transfer] / src / main / java / de / juplo / kafka / payment / transfer / domain / TransferService.java

diff --git a/src/main/java/de/juplo/kafka/payment/transfer/domain/TransferService.java b/src/main/java/de/juplo/kafka/payment/transfer/domain/TransferService.java
index 0cbcd2c..00c5478 100644 (file)
--- a/src/main/java/de/juplo/kafka/payment/transfer/domain/TransferService.java
+++ b/src/main/java/de/juplo/kafka/payment/transfer/domain/TransferService.java
@@ -4,26 +4,33 @@ package de.juplo.kafka.payment.transfer.domain;
 import de.juplo.kafka.payment.transfer.ports.*;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
-import org.apache.kafka.common.TopicPartition;
 
 import java.util.Optional;
-import java.util.concurrent.CompletableFuture;
 
 import static de.juplo.kafka.payment.transfer.domain.Transfer.State.CHECKED;
-import static de.juplo.kafka.payment.transfer.domain.Transfer.State.RECEIVED;
+import static de.juplo.kafka.payment.transfer.domain.Transfer.State.CREATED;
 
 
 @Slf4j
 @RequiredArgsConstructor
-public class TransferService implements ReceiveTransferUseCase, HandleTransferUseCase, GetTransferUseCase
+public class TransferService implements CreateTransferUseCase, HandleStateChangeUseCase, GetTransferUseCase
 {
   private final TransferRepository repository;
   private final MessagingService messagingService;
 
-  public CompletableFuture<TopicPartition> receive(Transfer transfer)
+  @Override
+  public void create(Transfer transfer)
   {
-    transfer.setState(RECEIVED);
-    return messagingService.send(transfer);
+    repository
+        .get(transfer.getId())
+        .ifPresentOrElse(
+            stored -> log.info("transfer already exisits: {}, ignoring: {}", stored, transfer),
+            () ->
+            {
+              log.info("creating transfer: {}", transfer);
+              repository.store(transfer);
+              messagingService.send(transfer.getId(), CREATED);
+            });
   }
 
   @Override
@@ -32,7 +39,7 @@ public class TransferService implements ReceiveTransferUseCase, HandleTransferUs
     Transfer.State state = transfer.getState();
     switch (state)
     {
-      case RECEIVED:
+      case CREATED:
         repository.store(transfer);
         check(transfer);
         break;
@@ -49,21 +56,8 @@ public class TransferService implements ReceiveTransferUseCase, HandleTransferUs
 
   private void check(Transfer transfer)
   {
-    repository
-        .get(transfer.getId())
-        .ifPresentOrElse(
-            stored ->
-            {
-              if (!transfer.equals(stored))
-                log.error("ignoring already received transfer with differing data: old={}, new={}", stored, transfer);
-            },
-            () ->
-            {
-              repository.store(transfer);
-              // TODO: Do some time consuming checks...
-              transfer.setState(CHECKED);
-              messagingService.send(transfer);
-            });
+    // TODO: Do some time consuming checks...
+    messagingService.send(transfer.getId(), CHECKED);
   }
 
   public Optional<Transfer> get(Long id)