CODEWITHSUNDEEP
swiftcore-data
Salah
Salah

Reputation: 953

How to create function with changeable attribute

I have custom function which is store data to Core data. But I don't want to duplicate the function many times depends on how many attributes i have. I want to create one function that i can use it with any attribute i want.

if #available(iOS 10.0, *) {
fetchRequest = MyUser.fetchRequest()//How to make this Changeable?
} else {
fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: changeableEntity)
}

Is there anyway that i can make the attribute "MyUser".fetchRequest() .. Changeable to any other attribute without duplicate the function many times?

class func MyCustomFunc(attribute: ??, changeableEntity:String)

Any help will be appreciated.

Upvotes: 0

Views: 55

Answers (1)

PongBongoSaurus
PongBongoSaurus

Reputation: 7385

You could use a function which passes the Object Type as a generic as per the following example:

/// Generates A Standard Fetch Request On A Generic NSManagedObject Type
///
/// - Parameter key: String
/// - Returns: NSFetchRequest<NSFetchRequestResult>

func generatedFetchRequestFor<Object: NSManagedObject>(_ key: String,  entityClass: Object.Type ) -> NSFetchRequest<NSFetchRequestResult>{

   var request: NSFetchRequest<NSFetchRequestResult>!

   if #available(iOS 10.0, *) {
      request = entityClass.fetchRequest()

   } else {
    let entityName = String(describing: entityClass)
    request = NSFetchRequest(entityName: entityName)

   }

   let sortDescriptor = NSSortDescriptor(key: key, ascending: true)
   request.sortDescriptors = [sortDescriptor]

  return request

}

An example use would thus be:

let request = generatedFetchRequestFor("id", entityClass: MyUser.self)

Upvotes: 1

Related Questions