data class BankTransferCommand(
  @NotNull
  val srcAccountId: UUID?,

  @NotNull
  val destAccountId: UUID?,

  @NotNull
  @DecimalMin(value = 100.0)
  @DecimalMax(value = 9999.0)
  val amount: Double?
)

@RpcController
class BankTransferRpcController(private val bankTransferService: BankTransferService) {

    @RpcHandler("bank.transfer")
    fun updateTenant(@Valid @RequestBody command: BankTransferCommand) {
        bankTransferService.execute(command)
    }
}

if (srcAccount.ownerId != destAccount.ownerId) {
  throw BankTransferMistachedOwnerException()
}

class BankAccount {
  private var balance: BigDecimal
  // other properties

  fun withdraw(withdrawalAmount: BigDecimal) {
    if (withdrawAmount > balance) {
      throw InsufficientFundsException()
    }
    balance -= withdrawalAmount
  }
}

class MyDatabaseConstraintViolationHandler : DatabaseConstraintViolationHandler {
  fun map(exception: DataIntegrityViolationException): DatabaseConstraintViolationException {
    if (exception.cause?.message?.contains("name") == true) {
      return UniqueConstraintViolationException(property = "name", message = "Name is already in use.")
    }
    return UnknownConstraintViolationException()
  }
}

@Service
class MyService(private val repository: WarehouseRepository) {

  @Transactional
  @ConstraintViolationHandler(MyDatabaseConstraintViolationHandler::class)
  fun execute(...) {
    .
    .
    .
  }
}

{
  errors: [
    {
      code: "error.required",
      property: "srcAccountId",
      message: "Source Account is required"
    },
    {
      code: "error.minValue",
      property: "amount",
      message: "Amount is below minimum.",
      context: {
        minValue: 100,
        minValueInclusive: true,
      }
    },
    {
      code: "error.mismatchedAccountOwners",
      message: "Accounts must have the same owner."
    }
  ]
}

class BankTransferMistmatchOwnerException
: ConstraintViolationException("error.mismatchedAccountOwners", "Accounts must have the same owner.")

@Component
class EmployeeEventGateway(private val eventBroker: EventBroker) {

  data class Payload(
    val employeeId: UUID
  )

  fun publishHomeAddressChangedEvent(employee: Employee) {
    eventBroker.publish(
      topic = "employee.homeAddressChanged",
      payload = Payload(employee.id)
    )
  }
}

@Component
class EmployeeEventGateway(private val eventBroker: EventBroker) {

  data class Payload(
    val employeeId: UUID,
    val homeAddress: Address
  )

  fun publishHomeAddressChangedEvent(employee: Employee, homeAddress: Address) {
    eventBroker.publish(
      topic = "employee.homeAddressChanged",
      payload = Payload(employee.id, homeAddress)
    )
  }
}

@EventController("4de4db8c-f888-4fa5-9b29-f11fe36b972c")
class DoSomethingEventController() {

  data class MyPayload(
    val employeeId: UUID,
    val homeAddress: Address
  )

  @EventHandler("employee.homeAddressChanged")
  fun employeeHomeAddressChanged(event: Event) {
    val payload = event.payload(MyPayload::class)
    .
    .
    .
  }
}

data class Payload(
  val employeeId: UUID,
  val zipCode: String
)

@Component
class EmployeeEventGateway(private val eventBroker: EventBroker) {

  data class OldPayload(
    val employeeId: UUID,
    val zipCode: String
  )

  data class NewPayload(
    val employeeId: UUID,
    val homeAddress: Address
  )

  fun publishHomeAddressChangedEvent(employee: Employee, homeAddress: Address) {
    val oldMessage = EventMessage(version = 0, payload = OldPayload(employee.id, homeAddress.zipCode))
    val newMessage = EventMessage(version = 1, payload = NewPayload(employee.id, homeAddress))
    eventBroker.publish(
      topic = "employee.homeAddressChanged",
      messages = listOf(oldMessage, newMessage))
    )
  }
}

@EventController("4de4db8c-f888-4fa5-9b29-f11fe36b972c")
class DoSomethingEventController() {

  data class Payload(
    val employeeId: UUID,
    val zipCode: String
  )

  @EventHandler("employee.homeAddressChanged", version = 0)
  fun employeeHomeAddressChanged(event: Event) {
    val payload = event.payload(Payload::class)
    .
    .
    .
  }
}

@EventController("4de4db8c-f888-4fa5-9b29-f11fe36b972c")
class DoSomethingEventController() {

  data class Payload(
    val employeeId: UUID,
    val zipCode: String
  )

  @EventHandler("employee.homeAddressChanged", version = 0)
  fun employeeHomeAddressChanged(event: Event) {
    val payload = event.payload(Payload::class)
    .
    .
    .
  }

  data class NewPayload(
    val employeeId: UUID,
    val address: Address
  )

  @EventHandler("employee.homeAddressChanged", version = 1)
  fun employeeHomeAddressChangedWithAddress(event: Event) {
    val payload = event.payload(NewPayload::class)
    .
    .
    .
  }
}

@Component
class SolarJobGateway(private val jobBroker: JobBroker) {

  fun submitJobToComputeSavings(designId: UUID, years: Int): UUID {
    val payload = mapOf("designId" to designId, "years" to years)
    return jobBroker.submit(
      queue = "design.computeSavings",
      payload = payload,
      onSuccessQueue = "design.computeSavings.onSuccess"
      onFailureQueue = "design.computeSavings.onFailure"
    )
  }
}

@JobController("design.computeSavings")
class ComputeSavingsJobController() {

  @JobHandler
  fun computeSavings(job: Job): Map<String, Any?> {
     val designId = job.payload["designId"]
     val years = job.payload["years"]
     val costSavings = compute(designId, years)
     return mapOf("costSavings" to costSavings)
  }
}

@JobController("design.computeSavings.onSuccess")
class ComputeSavingsSuccessJobController() {

  @JobHandler
  fun onSuccess(job: Job) {
     val designId = job.payload["designId"]
     val years = job.payload["years"]
     val costSavings = job.payload["costSavings"]
     .
     .
     .
  }
}

@JobController("design.computeSavings.onFailure")
class ComputeSavingsSuccessJobController() {

  @JobHandler
  fun onFailure(job: FailedJob) {
     val designId = job.payload["designId"]
     val years = job.payload["years"]
     val failure = job.failure
     println(failure.exceptionClass)
     println(failure.errorMessage)
     println(failure.stackTrace)
     .
     .
     .
  }
}