enum Temperature {
   TOO_HOT,
   TOO_COLD,
   JUST_RIGHT
}

@Managed
interface Item {
   void setName(String n); String getName()

   void setQuantity(int q); int getQuantity()

   void setPrice(float p); float getPrice()

   void setTemperature(Temperature t)
   Temperature getTemperature()

   void setDataFile(File f); File getDataFile()
}

class ItemRules extends RuleSource {
   @Model
   void item(Item item) {
      def data = item.dataFile.text.trim()
      def (name, quantity, price, temp) = data.split(',')
      item.name = name
      item.quantity = quantity
      item.price = price
      item.temperature = temp
   }

   @Defaults
   void setDefaults(Item item) {
      item.dataFile = 'data.csv'
   }

   @Mutate
   void createDataTask(ModelMap<Task> tasks, Item item) {
      tasks.create('showData') {
         doLast {
            println """
Item '$item.name'
   quantity:    $item.quantity
   price:       $item.price
   temperature: $item.temperature"""
         }
      }
   }
}

apply plugin: ItemRules

model {
   item {
      price = "${price * (quantity < 10 ? 2 : 0.5)}"
   }
}