added sequence generation of account numbers

transaction-service/src/main/java/cz/muni/fi/obs/data/TransactionServiceDataSeeder.java

+package cz.muni.fi.obs.data;
+
+import cz.muni.fi.obs.api.TransactionCreateDto;
+import cz.muni.fi.obs.data.dbo.AccountDbo;
+import cz.muni.fi.obs.data.repository.AccountRepository;
+import cz.muni.fi.obs.data.repository.ScheduledPaymentRepository;
+import cz.muni.fi.obs.data.repository.TransactionRepository;
+import cz.muni.fi.obs.service.TransactionService;
+import jakarta.annotation.PostConstruct;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnExpression;
+import org.springframework.stereotype.Component;
+
+import java.util.List;
+
+@Component
+@ConditionalOnExpression("${data.initialize:false}")
+@Slf4j
+public class TransactionServiceDataSeeder {
+
+    private final ScheduledPaymentRepository scheduledPaymentRepository;
+    private final TransactionRepository transactionRepository;
+    private final AccountRepository accountRepository;
+    private final TransactionService transactionService;
+
+    @Autowired
+    public TransactionServiceDataSeeder(AccountRepository accountRepository,
+                                        TransactionRepository transactionRepository,
+                                        ScheduledPaymentRepository scheduledPaymentRepository, TransactionService transactionService) {
+        this.accountRepository = accountRepository;
+        this.transactionRepository = transactionRepository;
+        this.scheduledPaymentRepository = scheduledPaymentRepository;
+        this.transactionService = transactionService;
+    }
+
+    @PostConstruct
+    public void initializeData() {
+        log.info("Initializing transaction service data...");
+
+        List<AccountDbo> accounts = createAccounts();
+        createScheduledPayments(accounts);
+
+        transactionService
+
+        createTransactions(accounts);
+        log.info("Initialized transaction service data...");
+    }
+
+    // TODO: implement
+    private void createTransactions(List<AccountDbo> accounts) {
+        TransactionCreateDto transactionCreateDto = new TransactionCreateDto();
+
+        transactionService.createTransaction(transactionCreateDto)
+    }
+
+    private List<AccountDbo> createAccounts() {
+        AccountDbo accountDbo = new AccountDbo();
+
+        accountRepository.save(accountDbo)
+    }
+
+    private void createScheduledPayments(List<AccountDbo> accounts) {
+    }
+}

transaction-service/src/main/java/cz/muni/fi/obs/data/dbo/AccountDbo.java

 package cz.muni.fi.obs.data.dbo;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.Id;
+import jakarta.persistence.SequenceGenerator;
 import jakarta.persistence.Table;
+import jakarta.persistence.Transient;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.EqualsAndHashCode;
@@ -27,6 +31,14 @@ public class AccountDbo {
 	private String customerId;
 	@Column(name = "currency_code", nullable = false)
 	private String currencyCode;
+	@GeneratedValue
+	@SequenceGenerator(name = "account_number_sequence", allocationSize = 1)
 	@Column(name = "account_number", nullable = false, unique = true)
-	private String accountNumber;
+	@JsonIgnore
+	private Integer accountNumber;
+
+	@Transient
+	private String getAccountNumber() {
+		return String.format("%08d", accountNumber);
+	}
 }

transaction-service/src/main/resources/db.migration/V2__account_number_sequence.sql

+ALTER TABLE accounts
+    ALTER COLUMN account_number SET DATA TYPE numeric(38, 0);
+CREATE SEQUENCE account_number_sequence START 1;
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