@startuml
'https://plantuml.com/class-diagram

class Channel
class ConsoleIO implements IO
class CSVFileIO implements FileIO{
List ReadFile()
void saveReport()
}
class DataProcessing{
parseStrings()
populateObjects
}
interface FileIO{
List ReadFile()
void saveReport()
}

interface IO
class Item
class Menu
class Order
class Region
class ReportContent{
public String toString()
}
class ServiceSales{
 HashMap<String,ArrayList<Order>> regionsWithOrders;
 HashMap <Long,Order> allOrders;
 ArrayList<Item> allItems;
 HashMap<String, Item> hashMapItems;
  public String getMostSoldItemToDisplay()
  public void displayMostSoldItemType() etc ...
}


CSVFileIO <|-- ReportContent
CSVFileIO <|--|> DataProcessing
DataProcessing --|> Order
DataProcessing --|> ServiceSales
DataProcessing --|> Region
DataProcessing --|> Item
DataProcessing --|> Channel
ServiceSales --|> ReportContent
ServiceSales --|> ConsoleIO
Order --|> ServiceSales
@enduml