cargo.clj

(ns layered-example.domain.cargo.cargo)                           
                                                                  
(defrecord Cargo [cargo-id size voyage-id])                       
                                                                  
(defn create-new-cargo [& {:keys [size voyage-id] :as cargo-data}]
  {:pre [(integer? size)                                          
         (nil? voyage-id)]}                                       
  (map->Cargo cargo-data))                                        
                                                                  
(defn book-onto-voyage [a-cargo & {:keys [voyage-id]}]            
  {:pre [(integer? voyage-id)                                     
         (nil? (:voyage-id a-cargo))]}                            
  (assoc a-cargo :voyage-id voyage-id))                           
                                                                  
(defn set-cargo-id [a-cargo cargo-id]                             
  {:pre [(not (:cargo-id a-cargo))]}                              
  (assoc a-cargo :cargo-id cargo-id))