add account not found exception

- update balance in AccountController with onErrorResume
- update AccountService
  - update getForUpdateById with switchIfEmpty
  - update getById with switchIfEmpty
- add AccountNotFoundException

src/main/kotlin/ltd/lulz/controller/AccountController.kt

@@ -39,6 +39,6 @@ class AccountController(
         @PathVariable account: UUID,
     ): Mono<Account.Response> = accountService.getById(account)
         .map { it.toResponse() }
-        .switchIfEmpty(Mono.error(ResponseStatusException(NOT_FOUND)))
+        .onErrorResume { Mono.error(ResponseStatusException(NOT_FOUND)) }
         .doOnError { log.debug { "account $account not found for balance" } }
 }

src/main/kotlin/ltd/lulz/exception/AccountNotFoundException.kt

@@ -0,0 +1,10 @@
+package ltd.lulz.exception
+
+@Suppress("unused")
+class AccountNotFoundException : RuntimeException {
+
+    constructor() : super()
+    constructor(message: String?) : super(message)
+    constructor(message: String?, cause: Throwable?) : super(message, cause)
+    constructor(cause: Throwable?) : super(cause)
+}

src/main/kotlin/ltd/lulz/service/AccountService.kt

@@ -2,6 +2,7 @@ package ltd.lulz.service
 
 import io.github.oshai.kotlinlogging.KotlinLogging
 import java.util.UUID
+import ltd.lulz.exception.AccountNotFoundException
 import ltd.lulz.model.AccountEntity
 import ltd.lulz.repository.AccountRepository
 import org.springframework.stereotype.Service
@@ -15,18 +16,28 @@ class AccountService(
     private val accountRepository: AccountRepository,
 ) {
 
-    fun create(entity: AccountEntity): Mono<AccountEntity> = accountRepository
+    fun create(
+        entity: AccountEntity,
+    ): Mono<AccountEntity> = accountRepository
         .save(entity)
         .doOnNext { log.debug { "account created with id: ${it.id}" } }
 
-    fun getById(id: UUID): Mono<AccountEntity> = accountRepository.findById(id)
+    fun getById(
+        id: UUID,
+    ): Mono<AccountEntity> = accountRepository.findById(id)
         .doOnNext { log.debug { "found account by id: ${it.id}" } }
+        .switchIfEmpty(Mono.error(AccountNotFoundException()))
 
     @Transactional
-    fun getForUpdateById(id: UUID): Mono<AccountEntity> = accountRepository.findByIdForUpdate(id)
+    fun getForUpdateById(
+        id: UUID,
+    ): Mono<AccountEntity> = accountRepository.findByIdForUpdate(id)
         .doOnNext { log.trace { "account with id: ${it.id} locked for update" } }
+        .switchIfEmpty(Mono.error(AccountNotFoundException()))
 
     @Transactional
-    fun save(entity: AccountEntity): Mono<AccountEntity> = accountRepository.save(entity)
+    fun save(
+        entity: AccountEntity,
+    ): Mono<AccountEntity> = accountRepository.save(entity)
         .doOnNext { log.trace { "account with id: ${it.id} saved" } }
 }