GroceryListView.java

@Templated
@Page
public class GroceryListView extends Composite {

  @PageState
  private long activeUserId;

  @Sync(query = "groceryListsForUser", 
    params = { @SyncParam(name = "userId", val = "{activeUserId}") })
  private void onDataSyncComplete(SyncResponses<GroceryList> responses) {
    Window.alert("Data Sync Complete!");
  }
  
}