Cómo evitar excepciones (pruebe catch block) como control de flujo

In the following method how can i aovid using try catch block but still call the correct method on id to get User/group? (Best Practices) Thanks in advance

     public Principal getPrincipal(String id) {
     Principal principal;
       try {
         principal = getUserById(id);
          return principal;

       } catch (Exception exception) {
        // nothing to do, maybe id is for group
    }

    principal = getGroup(id);
    return principal;
}

getUSerById(), throws a exception called EntityNotException,

preguntado el 12 de junio de 14 a las 10:06

As a best practice you should handle Checked Exceptions and your program should ideally not generate Unchecked Exceptions. -

puedes añadir throws Exception after method, like public Principal getPrincipal(String id) throws Exception{ en lugar de try..catch. -

As a general point, I'd be a bit more specific about the type of Exception that you catch. If you're only interested in the EntityNotException, only catch that exception. -

3 Respuestas

hacer función getUserById such way that if there is no user found it return null

public Principal getPrincipal(String id) {

Principal principal = getUserById(id);

if (principal == null) {
          principal = getGroup(id);
    }
  return principal;

}

Respondido el 12 de junio de 14 a las 10:06

There's no way to avoid try/catch block if you cannot modify getUserById(String) method. That's fine to have such check, but be very careful when you just ignore an exception.

Also you can just extract a small obtener el método Me gusta esto:

public Principal getUserByIdIngorinException(String id) {
    try {
        return getUserById(id);
    } catch (Exception ignored) {
        // ignore the exception
    }
    return null;
}

Respondido el 12 de junio de 14 a las 10:06

In that case I'd consider having your getUserById(String id) volvemos null, en lugar de un EntityNotException if no user can be found - Exceptions are to be used for Servicio circumstances, such as a failure beyond your control (Network connections vanished, no more memory is available, etc.). Your code could look something like the following:

public Principal getPrincipal(String id) {
    Principal principal = getUserById(id);

    if (principal == null) {
        //Try by group ID instead
        principal = getGroup(id);
    }
    return principal;
}

Make sure you're certain of the return types of your methods - from their names it doesn't sound like getUserById(String id) e getGroup(String id) definitely return a Principal object - the first sounds like it could return any type of User and the second a Group, sea lo que sea.

Alternatively, given the caller of this method presumably knows whether they have a userId o un groupId, have you considered separate methods getPrincipalByUserId(String userId) e getPrincipalByGroupId(String groupId)?

Respondido el 12 de junio de 14 a las 16:06

No es la respuesta que estás buscando? Examinar otras preguntas etiquetadas or haz tu propia pregunta.