EmployeeService.kt

@Service
class EmployeeService(private val employeeRepository: EmployeeRepository) {

    fun getAllEmployees(): List<Employee> = employeeRepository.findAll()

    fun getEmployeesById(employeeId: Long): Employee = employeeRepository.findById(employeeId)
            .orElseThrow { EmployeeNotFoundException(HttpStatus.NOT_FOUND, "No matching employee was found") }

    fun createEmployee(employee: Employee): Employee = employeeRepository.save(employee)

    fun updateEmployeeById(employeeId: Long, employee: Employee): Employee {
        return if (employeeRepository.existsById(employeeId)) {
            employeeRepository.save(
                    Employee(
                            id = employee.id,
                            userName = employee.userName,
                            firstName = employee.firstName,
                            middleName = employee.middleName,
                            lastName = employee.lastName,
                            emailId = employee.emailId,
                            dayOfBirth = employee.dayOfBirth
                    )
            )
        } else throw EmployeeNotFoundException(HttpStatus.NOT_FOUND, "No matching employee was found")
    }

    fun deleteEmployeesById(employeeId: Long) {
        return if (employeeRepository.existsById(employeeId)) {
            employeeRepository.deleteById(employeeId)
        } else throw EmployeeNotFoundException(HttpStatus.NOT_FOUND, "No matching employee was found")
    }
}