Update some comments

java/food-ordering/README.md

@@ -20,6 +20,12 @@ WebUI is running at http://localhost:3000
 
 Jaeger is running at http://localhost:16686
 
+When you are making changes to the code, and you want to trigger a build of the Docker images:
+
+```shell
+docker compose build --no-cache
+```
+
 Clean up after bringing setup down:
 ```shell
 docker compose rm 

java/food-ordering/app/restate-app/src/main/java/dev/restate/sdk/examples/DriverDigitalTwin.java

@@ -18,8 +18,8 @@
 
 /**
  * Digital twin for the driver. Represents a driver and his status, assigned delivery, and location.
- * Keyed by driver ID. The actual driver would have an application (mocked by DriverSimService) that
- * calls this service.
+ * Keyed by driver ID. The actual driver would have an application (mocked by DriverMobileAppSimulator
+ * ) that calls this service.
  */
 public class DriverDigitalTwin extends DriverDigitalTwinRestate.DriverDigitalTwinRestateImplBase {
 
@@ -36,7 +36,7 @@ public class DriverDigitalTwin extends DriverDigitalTwinRestate.DriverDigitalTwi
       StateKey.of("driver-location", JacksonSerdes.of(Location.class));
 
   /**
-   * When the driver starts his work day or finishes a delivery, his application (DriverSimService)
+   * When the driver starts his work day or finishes a delivery, his application (DriverMobileAppSimulator)
    * calls this method.
    */
   @Override
@@ -55,7 +55,7 @@ public void setDriverAvailable(RestateContext ctx, OrderProto.DriverAvailableNot
   }
 
   /**
-   * Gets called by the delivery service when this driver was assigned to do the delivery. Updates
+   * Gets called by the delivery manager when this driver was assigned to do the delivery. Updates
    * the status of the digital driver twin, and notifies the delivery service of its current
    * location.
    */
@@ -106,13 +106,15 @@ public void notifyDeliveryPickup(RestateContext ctx, OrderProto.DriverId request
     currentDelivery.notifyPickup();
     ctx.set(ASSIGNED_DELIVERY, currentDelivery);
 
-    // Update the status of the delivery in the delivery service
+    // Update the status of the delivery in the delivery manager
     DeliveryManagerRestate.newClient(ctx)
         .oneWay()
         .notifyDeliveryPickup(toOrderIdProto(currentDelivery.orderId));
   }
 
-  /** */
+  /**
+   * Gets called by the driver's mobile app when he has delivered the order to the customer.
+   */
   @Override
   public void notifyDeliveryDelivered(RestateContext ctx, OrderProto.DriverId request)
       throws TerminalException {

java/food-ordering/app/restate-app/src/main/java/dev/restate/sdk/examples/external/DriverMobileAppSimulator.java

@@ -21,7 +21,7 @@
  * This would actually be a mobile app that drivers use to accept delivery requests, and to set
  * themselves as available.
  *
- * <p>For simplicity, we implemented this with Restate.
+ * For simplicity, we implemented this with Restate.
  */
 public class DriverMobileAppSimulator
     extends DriverMobileAppSimulatorRestate.DriverMobileAppSimulatorRestateImplBase {
@@ -34,12 +34,14 @@ public class DriverMobileAppSimulator
   private final long PAUSE_BETWEEN_DELIVERIES = 2000;
 
   StateKey<Location> CURRENT_LOCATION =
-      StateKey.of("driversim-location", JacksonSerdes.of(Location.class));
+      StateKey.of("current-location", JacksonSerdes.of(Location.class));
 
   StateKey<AssignedDelivery> ASSIGNED_DELIVERY =
       StateKey.of("assigned-delivery", JacksonSerdes.of(AssignedDelivery.class));
 
-  /** */
+  /**
+   * Mimics the driver setting himself to available in the app
+   */
   @Override
   public void startDriver(RestateContext ctx, OrderProto.DriverId request)
       throws TerminalException {
@@ -74,15 +76,15 @@ public void startDriver(RestateContext ctx, OrderProto.DriverId request)
   @Override
   public void pollForWork(RestateContext ctx, OrderProto.DriverId request)
       throws TerminalException {
-    var driverSimClnt = DriverMobileAppSimulatorRestate.newClient(ctx);
+    var thisDriverSim = DriverMobileAppSimulatorRestate.newClient(ctx);
 
     // Ask the digital twin of the driver in the food ordering app, if he already got a job assigned
     var optionalAssignedDelivery =
         DriverDigitalTwinRestate.newClient(ctx).getAssignedDelivery(request).await();
 
     // If there is no job, ask again after a short delay
     if (optionalAssignedDelivery.hasEmpty()) {
-      driverSimClnt.delayed(Duration.ofMillis(POLL_INTERVAL)).pollForWork(request);
+      thisDriverSim.delayed(Duration.ofMillis(POLL_INTERVAL)).pollForWork(request);
       return;
     }
 
@@ -98,9 +100,12 @@ public void pollForWork(RestateContext ctx, OrderProto.DriverId request)
     ctx.set(ASSIGNED_DELIVERY, newAssignedDelivery);
 
     // Start moving to the delivery pickup location
-    driverSimClnt.delayed(Duration.ofMillis(MOVE_INTERVAL)).move(request);
+    thisDriverSim.delayed(Duration.ofMillis(MOVE_INTERVAL)).move(request);
   }
 
+  /**
+   * Periodically lets the food ordering app know the new location
+   */
   @Override
   public void move(RestateContext ctx, OrderProto.DriverId request) throws TerminalException {
     var thisDriverSim = DriverMobileAppSimulatorRestate.newClient(ctx);

java/food-ordering/docker-compose.yaml

@@ -89,6 +89,7 @@ services:
     ports:
       - "9070:9070"
       - "9071:9071"
+      - "9072:9072"
       - "8080:8080"
     volumes:
       - ./restate-docker.yaml:/restate.yaml