Use toString() for retrieving a string representation of TrackingId and CarrierId instead of repeated id accessor.

dddsample/src/main/java/se/citerus/dddsample/domain/CarrierId.java

     this.id = id;
   }
 
-  public String id() {
+  @Override
+  public String toString() {
     return id;
   }
 

dddsample/src/main/java/se/citerus/dddsample/domain/TrackingId.java

     this.id = id;
   }
 
-  public String id() {
+  @Override
+  public String toString() {
     return id;
   }
 

dddsample/src/main/java/se/citerus/dddsample/repository/CargoRepositoryInMem.java

 package se.citerus.dddsample.repository;
 
-import java.util.HashMap;
-import java.util.Map;
-
 import org.springframework.dao.DataRetrievalFailureException;
-
 import se.citerus.dddsample.domain.Cargo;
 import se.citerus.dddsample.domain.HandlingEvent;
 import se.citerus.dddsample.domain.Location;
 import se.citerus.dddsample.domain.TrackingId;
 
+import java.util.HashMap;
+import java.util.Map;
+
 /**
  * CargoRepositoryInMem implement the CargoRepository interface but is a test
  * class not intended for usage in real application.
   }
 
   public Cargo find(TrackingId trackingId) {
-    if (trackingId.id().equalsIgnoreCase("DAE")){
+    if (trackingId.toString().equalsIgnoreCase("DAE")){
       throw new DataRetrievalFailureException("Network failure. Please try again");
     }
     
-    return cargoDb.get(trackingId.id());
+    return cargoDb.get(trackingId.toString());
   }
   
   public void save(Cargo cargo) {

dddsample/src/main/java/se/citerus/dddsample/service/CargoServiceImpl.java

       return null;
     }
     final CargoWithHistoryDTO dto = new CargoWithHistoryDTO(
-            cargo.trackingId().id(),
+            cargo.trackingId().toString(),
             cargo.origin().unlocode(),
             cargo.finalDestination().unlocode(),
             cargo.currentLocation().unlocode()
     for (HandlingEvent event : events) {
       CarrierMovement cm = event.carrierMovement();
       String carrierIdString =
-              (cm == null) ? Location.UNKNOWN.unlocode() : cm.carrierId().id();
+              (cm == null) ? Location.UNKNOWN.unlocode() : cm.carrierId().toString();
       dto.addEvent(new HandlingEventDTO(
               event.location().unlocode(),
               event.type().toString(),

dddsample/src/test/java/se/citerus/dddsample/web/CargoTrackingControllerTest.java

 
         // TODO: use DTO assemblers
         CargoWithHistoryDTO cargoDTO = new CargoWithHistoryDTO(
-                cargo.trackingId().id(),
+                cargo.trackingId().toString(),
                 cargo.origin().unlocode(),
                 cargo.finalDestination().unlocode(),
                 cargo.currentLocation().unlocode()