Swift: "Mapper is not a type", using custom mapping class for arrays in swift and Objective C - objective-c

Question

I have an 2 objective C classes:
Class 1 scanDatabase (Scans a database and puts that into a mutable array)
Class 2 Mapper (Is a mapping class for the database scan "model")
In objective C this successfully scans the database and puts it into a mutable array. Using the mapping class I can access individual groups of elements (AlbumTitles) like so:
for (Mapper *mapper in scanResult) {
NSLog(#"%#", mapper.AlbumTitle);
}
Everything is working as it should and I can return individual elements from my array i.e as above I am only returning album titles.
I then need to use that array in Swift. I call the objective C in my Swift class and again it runs fine and creates the array. This is done with:
let scanTable = ScanTable();
let scanMapper = Mapper();
scanTable.scanTableDo();
but when I try to retrieve a particular set of items like Album title as I did in the objective C for loop above I get the error "scanMapper is not a type" (scanMapper is my swift instance of the objective C mapper class:
I tried two different ways and both have the same error:
for mapper: scanMapper in scanTable.scanResult {
print("\(mapper.AlbumTitle)")
}
for object in scanTable.scanResult as! [scanMapper] {
print("\(mapper.AlbumTitle)")
}
Can I use an objective C class as a model/mapper and not sure whether I would need to recreate it in Swift.
I will include the mapper and scanTable .h and .m code just in case it is needed, plus the bridging header:
Mapper.h:
#import <Foundation/Foundation.h>
#import <AWSDynamoDB/AWSDynamoDB.h>
#interface Mapper : AWSDynamoDBObjectModel <AWSDynamoDBModeling>
#property (nonatomic, strong) NSNumber *SongID;
#property (nonatomic, strong) NSString *Artist;
#property (nonatomic, strong) NSString *SongURL;
#property (nonatomic, strong) NSString *Location;
#property (nonatomic, strong) NSNumber *UserRatings;
#property (nonatomic, strong) NSNumber *AVGUserRating;
#property (nonatomic, strong) NSString *Category;
#property (nonatomic, strong) NSString *PictureURL;
#property (nonatomic, strong) NSNumber *SongDuration;
#property (nonatomic, strong) NSString *SongTitle;
#property (nonatomic, strong) NSNumber *AVGMusicianRating;
#property (nonatomic, strong) NSString *AlbumTitle;
#end
Mapper.m
#import <AWSDynamoDB/AWSDynamoDB.h>
#import "Mapper.h"
#implementation Mapper
+ (NSString *)dynamoDBTableName {
return #"Songs";
}
+ (NSString *)hashKeyAttribute {
return #"SongID";
}
#end
ScanTable.h:
#import <Foundation/Foundation.h>
#import <AWSDynamoDB/AWSDynamoDB.h>
#interface ScanTable : NSObject
- (void) scanTableDo;
#property (nonatomic, strong) NSMutableArray *scanResult;
#end
ScanTable.m
#import "ScanTable.h"
#import "Mapper.h"
#implementation ScanTable
- (void) scanTableDo {
AWSDynamoDBObjectMapper *dynamoDBObjectMapper = [AWSDynamoDBObjectMapper defaultDynamoDBObjectMapper];
AWSDynamoDBScanExpression *scanExpression = [AWSDynamoDBScanExpression new];
scanExpression.limit = #10;
[[dynamoDBObjectMapper scan:[Mapper class]
expression:scanExpression]
continueWithBlock:^id(AWSTask *task) {
if (task.error) {
NSLog(#"The request failed. Error: [%#]", task.error);
}
if (task.exception) {
NSLog(#"The request failed. Exception: [%#]", task.exception);
}
if (task.result) {
AWSDynamoDBPaginatedOutput *paginatedOutput = task.result;
NSMutableArray *scanResult = [[NSMutableArray alloc] initWithArray:paginatedOutput.items]; //// ADDED /////
for (Mapper *mapper in scanResult) {
NSLog(#"%#", mapper.AlbumTitle);
}
}
return nil;
}];
}
#end
//EDITED ADDED BRIDGING HEADER//
MySampleApp-Bridging-Header.h:
//
// MySampleApp-Bridging-Header.h
// MySampleApp
#import "ScanTable.h"
#import "Mapper.h"
#import "Hello World.h"
Thanks for your help

Answer 1

The problem is just as the error explains, you're attempting to cast the items in your array to scanMapper, which is a variable holding an instance of Mapper, not the Mapper type itself. Assuming that scanTable.scanResult is an NSArray of Mappers, try this instead:
guard let scanResult = scanTable.scanResult as? [Mapper] else {
print("scanResult was not an array of mappers!")
return
}
for mapper: Mapper in scanResult {
print("\(mapper.AlbumTitle)")
}