Find an integer value in Objective-C enum

Question

Is it possible in Objective-C to see if a int value is in a particular enum? For instance, in this enum:

enum  {
  ValidationLoginFailed         = 2000,
  ValidationSessionTokenExpired = 2001,
  ValidationSessionTokenInvalid = 2002,
  ValidationEmailNotFound       = 2003  
}; 
typedef int ValidationStatusCodes;

is it possible to see if an arbitrary integer value is in the ValidationStatusCodes enum?

[ValidationStatusCodes contains:intResponseCode]

or at least

[self intIsInRangeofEnum:ValidationStatusCodes forValue:intResponseCode]

Answer 1

There's no simpler way than just doing

(ValidationLoginFailed == intResponseCode ||
ValidationSessionTokenExpired == intResponseCode ||
ValidationSessionTokenInvalid == intResponseCode ||
ValidationEmailNotFound == intResponseCode)

In general, C is not very helpful for doing dynamic things or reflecting on types, and enums are a C feature.

Answer 2

Not with an enum. An enum is not an objective-C object, so you can't send it messages as you're doing.

Maybe use an NSDictionary?

Answer 3

This question is a little dated, but the standard I have seen in software design is to use a bitmask where each of these values is a discrete state with a bit-shift. In some cases, your enum values can be combinations of other values.

enum  {
  ValidationLoginFailed         = 0, //0
  ValidationSessionTokenExpired = 1 << 0, //1
  ValidationSessionTokenInvalid = 1 << 1, //2
  ValidationEmailNotFound       = 1 << 2  //4
}; 
typedef int ValidationStatusCodes;

For your use-case you would & your result with all of the items in the set:

int allStates = (ValidationLoginFailed | ValidationSessionTokenExpired | 
   ValidationSessionTokenInvalid | ValidationEmailNotFound); //7

if(val & allStates){
   //some logic here
}