Items Processor

import java.util.List;
import java.util.Map;

class Main {
    public static void main(String[] args) {
        List<Item> items = List.of(
            new Item("Mouse", 15.0),    // Cheap
            new Item("Mouse", 25.0),    // Moderate
            new Item("Keyboard", 120.0), // Expensive
            new Item("Mouse", 10.0)     // Cheap
        );
        
        ItemProcessor processor = new ItemProcessorImpl();
        
        Map<String, Integer> byCategory = processor.countItemsByCategory(items);
        
        byCategory.forEach((k,v) -> System.out.println(k + ": " + v));
        
        Map<String, Double> discounts = processor.calculateTotalDiscounts(items);
        
        discounts.forEach((k,v) -> System.out.println(k + ": " + v));
        
        Map<String, Integer> byName = processor.countItemsByName(items);
        
        byName.forEach((k,v) -> System.out.println(k + ": " + v));
    }
}