Fixed bug when trying to find a nonexisting cargo.

dddsample/src/main/java/se/citerus/dddsample/application/persistence/CargoRepositoryHibernate.java

     // Query for id and then perform a standard load()
     // to use metadata-defined query and lazy proxy access
     Long id = (Long) getSession().
-            createQuery("select id from Cargo where trackingId = :tid").
-            setParameter("tid", tid).
-            uniqueResult();
+       createQuery("select id from Cargo where trackingId = :tid").
+       setParameter("tid", tid).
+       uniqueResult();
+
+    if (id != null) {
+      return (Cargo) getSession().get(Cargo.class, id);
+    } else {
+      return null;
+    }
+
 
-    return (Cargo) getSession().load(Cargo.class, id);
   }
 
   public void save(Cargo cargo) {
     // Delete orphaned itineraries - conceptually the responsibility
     // of the Cargo aggregate
     final List<Itinerary> orphans = getSession().
-      createQuery("from Itinerary where cargo = null").
-      list();
+       createQuery("from Itinerary where cargo = null").
+       list();
     for (Itinerary orphan : orphans) {
       getSession().delete(orphan);
     }
   public TrackingId nextTrackingId() {
     final String random = UUID.randomUUID().toString().toUpperCase();
     return new TrackingId(
-      random.substring(0, random.indexOf("-"))
+       random.substring(0, random.indexOf("-"))
     );
   }
 

dddsample/src/main/java/se/citerus/dddsample/domain/model/cargo/CargoRepository.java

    * Finds a cargo using given id.
    *
    * @param trackingId Id
-   * @return Cargo
+   * @return Cargo if found, else {@code null}
    */
   Cargo find(TrackingId trackingId);
 

dddsample/src/test/java/se/citerus/dddsample/application/persistence/CargoRepositoryTest.java

     assertEquals(cargo, event.cargo());
   }
 
+  public void testFindByCargoIdUnknownId() {
+    assertNull(cargoRepository.find(new TrackingId("UNKNOWN")));
+  }
+
   private void assertLeg(Leg firstLeg, String cmId, Location expectedFrom, Location expectedTo) {
     assertEquals(new CarrierMovementId(cmId), firstLeg.carrierMovement().carrierMovementId());
     assertEquals(expectedFrom, firstLeg.from());