Overview
The ObtenerReserva use case provides a simple interface to retrieve all reservations from the system. It handles errors gracefully by returning an empty list if the query fails.
Constructor
ObtenerReserva(ReservaRepositorio reservaRepositorio)
Dependencies
reservaRepositorio
ReservaRepositorio
required
Repository for querying reservation data
ejecutar() Method
Retrieves all reservations from the repository.
Future<List<Reserva>> ejecutar()
Parameters
This method takes no parameters.
Return Value
Returns a Future<List<Reserva>> containing:
- All reservations in the system if the query succeeds
- An empty list
[] if an error occurs during retrieval
Error Handling
This use case implements defensive error handling:
- Catches any exceptions thrown by the repository
- Returns an empty list instead of propagating the exception
- Can be modified to throw exceptions by uncommenting the throw statement in the implementation
Usage Example
Basic Usage
// Initialize repository
final reservaRepo = FirebaseReservaRepositorio();
// Create use case instance
final obtenerReserva = ObtenerReserva(reservaRepo);
// Retrieve all reservations
final reservas = await obtenerReserva.ejecutar();
if (reservas.isEmpty) {
print('No hay reservas o ocurrió un error');
} else {
print('Se encontraron ${reservas.length} reservas');
for (final reserva in reservas) {
print('- ${reserva.id}: ${reserva.nombreCliente} (${reserva.estado})');
}
}
Filtering Reservations
Since this method returns all reservations, you typically need to filter them based on your needs:
final reservas = await obtenerReserva.ejecutar();
// Filter by date
final hoy = DateTime.now();
final reservasHoy = reservas.where((r) =>
r.fechaHora.year == hoy.year &&
r.fechaHora.month == hoy.month &&
r.fechaHora.day == hoy.day
).toList();
// Filter by state
final reservasConfirmadas = reservas.where((r) =>
r.estado == EstadoReserva.confirmada
).toList();
// Filter by business
final reservasNegocio = reservas.where((r) =>
r.negocioId == 'negocio-001'
).toList();
// Filter by table
final reservasMesa = reservas.where((r) =>
r.mesaId == 'mesa-001'
).toList();
Sorting Reservations
final reservas = await obtenerReserva.ejecutar();
// Sort by date (ascending)
reservas.sort((a, b) => a.fechaHora.compareTo(b.fechaHora));
// Sort by date (descending - most recent first)
reservas.sort((a, b) => b.fechaHora.compareTo(a.fechaHora));
// Sort by number of people
reservas.sort((a, b) => b.numeroPersonas.compareTo(a.numeroPersonas));
Display in UI
class ReservationsPage extends StatefulWidget {
@override
_ReservationsPageState createState() => _ReservationsPageState();
}
class _ReservationsPageState extends State<ReservationsPage> {
late ObtenerReserva _obtenerReserva;
List<Reserva> _reservas = [];
bool _loading = true;
@override
void initState() {
super.initState();
_obtenerReserva = ObtenerReserva(getIt<ReservaRepositorio>());
_loadReservations();
}
Future<void> _loadReservations() async {
setState(() => _loading = true);
final reservas = await _obtenerReserva.ejecutar();
setState(() {
_reservas = reservas;
_loading = false;
});
}
@override
Widget build(BuildContext context) {
if (_loading) {
return Center(child: CircularProgressIndicator());
}
if (_reservas.isEmpty) {
return Center(child: Text('No hay reservas'));
}
return ListView.builder(
itemCount: _reservas.length,
itemBuilder: (context, index) {
final reserva = _reservas[index];
return ListTile(
title: Text(reserva.nombreCliente ?? 'Cliente sin nombre'),
subtitle: Text(
'${_formatDate(reserva.fechaHora)} - ${reserva.numeroPersonas} personas'
),
trailing: _buildStatusChip(reserva.estado),
);
},
);
}
String _formatDate(DateTime date) {
return '${date.day}/${date.month}/${date.year} ${date.hour}:${date.minute.toString().padLeft(2, '0')}';
}
Widget _buildStatusChip(EstadoReserva estado) {
Color color;
switch (estado) {
case EstadoReserva.confirmada:
color = Colors.green;
break;
case EstadoReserva.pendiente:
color = Colors.orange;
break;
case EstadoReserva.cancelada:
color = Colors.red;
break;
}
return Chip(
label: Text(estado.toString().split('.').last),
backgroundColor: color.withOpacity(0.2),
);
}
}
Implementation Notes
Current Behavior
The current implementation returns an empty list on errors, which means:
- Advantage: The UI won’t crash if there’s a database error
- Disadvantage: You can’t distinguish between “no reservations” and “error occurred”
Alternative Implementation
If you need to handle errors explicitly, you can modify the use case to throw exceptions:
Future<List<Reserva>> ejecutar() async {
try {
return await reservaRepositorio.obtenerReserva();
} catch (e) {
throw Exception('Error al obtener reservas: $e');
}
}
try {
final reservas = await obtenerReserva.ejecutar();
// Display reservations
} on Exception catch (e) {
// Show error message to user
showError('No se pudieron cargar las reservas');
}
Limitations
This use case has some limitations to be aware of:
- No Filtering: Retrieves ALL reservations, which may be inefficient for large datasets
- No Pagination: All results returned at once
- No Business Scope: Returns reservations from all businesses
- No Date Range: Cannot limit to specific date ranges
Recommended Enhancements
For production use, consider creating additional use cases or extending this one:
// Obtain reservations for a specific business
Future<List<Reserva>> ejecutarPorNegocio(String negocioId)
// Obtain reservations for a date range
Future<List<Reserva>> ejecutarPorRangoFechas(
DateTime inicio,
DateTime fin,
)
// Obtain reservations by state
Future<List<Reserva>> ejecutarPorEstado(
EstadoReserva estado,
)
// Obtain reservations with pagination
Future<List<Reserva>> ejecutarConPaginacion(
int limite,
String? ultimoId,
)
