Enum Transformations

To map enums use the JMTransformerProtocol. Let's look at a dictionary for a business object, and see how we can map an enum to represent the type of business:

Response Dictionary

{
    'business_uuid'  	: 9223123456754775807,
    'business_name'  	: 'NYC Restaurant',
    'business_type'     : 'Lounge'
}

Unlike the model objects, JSONModelKit does not autogenerate enums, due to the fact they would be un-customizable. This would prevent the developer from using the many features Swift offers with enums. For the purposes of the example, let's assume that a business_type key value parsed can be 'Lounge', 'Dinner', and 'Coffee Shop'. First, create an enum to represent the business type for our custom Business Object:

Enum Definition

enum BusinessType : Int {
    case Unknown = 0, Lounge, Dinner, CoffeeShop
}

Once we have defined a BusinessType enum, create a mapper that parses out the values from the response and return the BusinessType type enum value.

JSONModelKitCoordinateTransformer Implementation

let businessTypeKey    = "business_type"

public class JSONModelKitCoordinateTransformer : JMTransformerProtocol {
    public func transformValues(inputValues : Dictionary<String, Any>?) -> Any? {

        if let typeValue = inputValues![businessTypeKey] as? String {
            switch typeValue {
                case "Lounge":
                    return BusinessType.Lounge
                case "Dinner":
                    return BusinessType.Dinner
                case "CoffeeShop":
                    return BusinessType.CoffeeShop
                default:
                    return BusinessType.Unknown
            }
        }
        return nil
    }
}

Now that we have created a transformeer let's create some mapping for our business Object:

JSON: /Model/Mappings/Business.json	PLIST: /Mappings/Business.plist

After the creation of the mapping, perform a build **(⌘-B)**. The changes should be reflected accordingly in the internal `_Business.swift` class.

import Foundation
import JSONModelKit

class _Business {
	var uuid : Double?
	var name : String?
	var businessType : BusinessType?

 	required init() {...}

 	convenience init?(_ dictionary: Dictionary<String, Any>) {...}
}

After calling the fail-able initializer - or udpateWithDictionary method with a dictionary representation - JSONModelKit will use the custom transformer to map the enumerator accordingly.

Note: The the keys defined in the property mapping correspond to the keys in the dictionary of values passed to the public func transformValues(inputValues : Dictionary<String, Any>?) -> Any? method defined by the protocol.