Change update return Wallet

this is fix concurrency update

src/main/java/com/bifurcated/wallet/data/WalletRepo.java

@@ -1,8 +1,27 @@
 package com.bifurcated.wallet.data;
 
+import org.springframework.data.jdbc.repository.query.Query;
 import org.springframework.data.repository.CrudRepository;
 
+import java.util.Optional;
 import java.util.UUID;
 
 public interface WalletRepo extends CrudRepository<Wallet, UUID> {
+
+    @Query("""
+         UPDATE wallet
+         SET amount = (amount + :amount)
+         WHERE id = :id
+         RETURNING id, amount
+    """)
+    Optional<Wallet> updateAmount(UUID id, Float amount);
+
+    @Query("""
+         UPDATE wallet
+         SET amount = (amount - :amount)
+         WHERE id = :id
+         RETURNING id, amount
+    """)
+    Wallet updateAmountReduce(UUID id, Float amount);
+
 }

src/main/java/com/bifurcated/wallet/service/WalletService.java

@@ -5,14 +5,8 @@
 import com.bifurcated.wallet.errors.NotEnoughMoneyError;
 import com.bifurcated.wallet.errors.WalletNotFoundError;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.retry.annotation.Backoff;
-import org.springframework.retry.annotation.Retryable;
 import org.springframework.stereotype.Service;
-import org.springframework.transaction.annotation.Isolation;
-import org.springframework.transaction.annotation.Propagation;
-import org.springframework.transaction.annotation.Transactional;
 
-import java.sql.SQLException;
 import java.util.UUID;
 
 
@@ -25,25 +19,17 @@ public WalletService(WalletRepo walletRepo) {
         this.walletRepo = walletRepo;
     }
 
-    @Transactional(
-            isolation = Isolation.SERIALIZABLE,
-            propagation = Propagation.REQUIRES_NEW)
-    @Retryable(retryFor = SQLException.class, maxAttempts = 17, backoff = @Backoff(delay = 500))
     public Wallet addAmount(UUID id, Float amount) {
-        var wallet = walletRepo.findById(id).orElseThrow(WalletNotFoundError::new);
-        wallet.setAmount(wallet.getAmount() + amount);
-        return walletRepo.save(wallet);
+        return walletRepo.updateAmount(id, amount).orElseThrow(WalletNotFoundError::new);
     }
 
-    @Transactional
     public Wallet reduceAmount(UUID id, Float amount) {
         var wallet = walletRepo.findById(id).orElseThrow(WalletNotFoundError::new);
         var reduce = wallet.getAmount() - amount;
         if (reduce < 0) {
             throw new NotEnoughMoneyError(wallet.getAmount(), amount);
         }
-        wallet.setAmount(reduce);
-        return walletRepo.save(wallet);
+        return walletRepo.updateAmountReduce(id, amount);
     }
 
     public Float amount(UUID id) {