         error: (NSError -> Void)?
         ) {
             cacheFile = NSURL()
-            errorCompletion = error
-            self.completion = completion
+            _error = error
+            _completion = completion
             
             super.init(operations: [])
             name = "DownloadJSONOperation<\(self.dynamicType)>"

                let json = try NSJSONSerialization.JSONObjectWithData(data,
                    options: .MutableContainers
                    ) as? [String:AnyObject]
                completion?(json)
            } catch let error as NSError {
                errorCompletion?(error)
                finishWithError(error)
                
                return

    // MARK: - Public Properties/Overridables
    public let cacheFile: NSURL
    
    public var endpointType: EndpointType {
        return .Simple
    }
