Encoding and Decoding for NSUserDefaults

gistfile1.swift

class Product : NSObject, NSCoding {
    
    let nameKey = "name"
    let qtyKey = "qty"
    
    var name : String = ""
    var qty : Int = 0
    
    required init(coder aDecoder: NSCoder) {
        if let name = aDecoder.decodeObjectForKey(nameKey) as? String {
            self.name = name
        }
        
        if let qty = aDecoder.decodeObjectForKey(qtyKey) as? Int {
            self.qty = qty
        }

    }
    
    func encodeWithCoder(aCoder: NSCoder) {
        aCoder.encodeObject(self.name, forKey: nameKey)
        aCoder.encodeObject(self.qty, forKey: qtyKey)
    }
}