Struct 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 a struct for the coordinates:

Response Dictionary

{
    'business_uuid'  	 : 9223123456754775807,
    'business_name'  	 : 'NYC Restaurant',
    'business_longitude' : 40.7053319,
    'business_latitude'  : -74.0129945,
}

Unlike the model objects, JSONModelKit does not autogenerate structs, due to the lack of inheritance. Structs would be un-customizable if it did, and would prevent the developer from using the many features Swift offers with structs. For the purposes of this example, let assume that we created a struct to represent the coordinates for our custom Business Object.

Struct Definition

struct Coordinate {
   var longitude: Double
   var latitude: Double
}

Once we have defined a Coordinate struct, let's create a mapper that parses out the values from the response and return the value of Coordinate type.

JMTransformerProtocol Implementation

let longitudeKey    = "business_longitude"
let latitudeKey     = "business_latitude"

public class CoordinateTransformer : JMTransformerProtocol {

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

        if let coordinateDictionary = inputValues as? Dictionary<String, Double>,
           let longitude = coordinateDictionary[longitudeKey], 
           let latitude = coordinateDictionary[latitudeKey] {
                    return Coordinate(longitude : longitude, latitude : latitude)
                }
            }
        }

        return nil
    }
}

Mapping

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

/Model/Mappings/Business.json | PLIST Equivalent

{
    "uuid" : { ... },
    "fullName" : {
	"transformer" : "CoordinateTransformer",
        "type" : "Coordinate",
        "key" : [
	    "business_longitude",
	    "business_latitude"
	]
    }
}

Model

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 coordinates : Coordinates?

 	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 struct 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.