Update Javadoc

src/ext/java/org/opentripplanner/ext/siri/TimetableHelper.java

@@ -688,10 +688,10 @@ public static List<StopTime> createModifiedStopTimes(
    * all trips in a timetable are from the same feed, which should always be the case.
    *
    * @param activity SIRI-VM VehicleActivity
-   * @return new copy of updated TripTimes after TripUpdate has been applied on TripTimes of trip
-   * with the id specified in the trip descriptor of the TripUpdate; null if something went wrong
+   * @return a Result with a copy of updated TripTimes after TripUpdate has been applied on TripTimes of trip
+   * with the id specified in the trip descriptor of the TripUpdate; a failed Result if something went wrong
    */
-  public static Result<UpdateError, TripTimes> createUpdatedTripTimes(
+  public static Result<TripTimes, UpdateError> createUpdatedTripTimes(
     Timetable timetable,
     VehicleActivityStructure activity,
     FeedScopedId tripId,

src/main/java/org/opentripplanner/common/model/Result.java

@@ -9,15 +9,15 @@
  * <p>
  * It's very similar to the Either or Validation type found in functional programming languages.
  */
-public abstract class Result<E, T> {
+public abstract sealed class Result<T, E> {
 
   private Result() {}
 
-  public static <E, T> Result<E, T> failure(@Nonnull E failure) {
+  public static <T, E> Result<T, E> failure(@Nonnull E failure) {
     return new Failure<>(failure);
   }
 
-  public static <E, T> Result<E, T> success(@Nonnull T success) {
+  public static <T, E> Result<T, E> success(@Nonnull T success) {
     return new Success<>(success);
   }
 
@@ -83,7 +83,7 @@ public T successValue() {
     }
   }
 
-  private static class Failure<E, T> extends Result<E, T> {
+  private static final class Failure<T, E> extends Result<T, E> {
 
     private final E failure;
 
@@ -110,7 +110,7 @@ public void ifFailure(Consumer<E> func) {
     }
   }
 
-  private static class Success<E, T> extends Result<E, T> {
+  private static final class Success<T, E> extends Result<T, E> {
 
     private final T success;
 

src/main/java/org/opentripplanner/model/Timetable.java

@@ -146,22 +146,22 @@ public TripTimes setTripTimes(int tripIndex, TripTimes tt) {
    * @param updateServiceDate             service date of trip update
    * @param backwardsDelayPropagationType Defines when delays are propagated to previous stops and
    *                                      if these stops are given the NO_DATA flag
-   * @return {@link TripTimesPatch} that contains a new copy of updated TripTimes after TripUpdate
-   * has been applied on TripTimes of trip with the id specified in the trip descriptor of the
-   * TripUpdate and a list of stop indices that have been skipped with the realtime update; null if
-   * something went wrong
+   * @return {@link Result<TripTimesPatch, UpdateError>} contains either a new copy of updated
+   * TripTimes after TripUpdate has been applied on TripTimes of trip with the id specified in the
+   * trip descriptor of the TripUpdate and a list of stop indices that have been skipped with the
+   * realtime update; or an error if something went wrong
    * <p>
    * TODO OTP2 - This method depend on GTFS RealTime classes. Refactor this so GTFS RT can do
    *           - its job without sending in GTFS specific classes. A generic update would support
    *           - other RealTime updats, not just from GTFS.
    */
-  public Result<UpdateError, TripTimesPatch> createUpdatedTripTimes(
+  public Result<TripTimesPatch, UpdateError> createUpdatedTripTimes(
     TripUpdate tripUpdate,
     ZoneId timeZone,
     LocalDate updateServiceDate,
     BackwardsDelayPropagationType backwardsDelayPropagationType
   ) {
-    Result<UpdateError, TripTimesPatch> generalError = Result.failure(
+    Result<TripTimesPatch, UpdateError> generalError = Result.failure(
       UpdateError.noTripId(UNKNOWN)
     );
     if (tripUpdate == null) {

src/main/java/org/opentripplanner/updater/stoptime/TimetableSnapshotSource.java

@@ -472,7 +472,7 @@ private Optional<UpdateError> handleScheduledTrip(
    *
    * @param tripUpdate     GTFS-RT TripUpdate message
    * @param tripDescriptor GTFS-RT TripDescriptor
-   * @return true if successful
+   * @return empty Optional if successful or one containing en error
    */
   private Optional<UpdateError> validateAndHandleAddedTrip(
     final TripUpdate tripUpdate,
@@ -621,7 +621,7 @@ private List<StopLocation> checkNewStopTimeUpdatesAndFindStops(
    * @param tripDescriptor GTFS-RT TripDescriptor
    * @param stops          the stops of each StopTimeUpdate in the TripUpdate message
    * @param serviceDate    service date for added trip
-   * @return true if successful
+   * @return empty Optional if successful or one containing en error
    */
   private Optional<UpdateError> handleAddedTrip(
     final TripUpdate tripUpdate,
@@ -716,7 +716,7 @@ private Optional<UpdateError> handleAddedTrip(
    * @param stops         list of stops corresponding to stop time updates
    * @param serviceDate   service date of trip
    * @param realTimeState real-time state of new trip
-   * @return true if successful
+   * @return empty Optional if successful or one containing en error
    */
   private Optional<UpdateError> addTripToGraphAndBuffer(
     final Trip trip,
@@ -906,7 +906,7 @@ private Optional<UpdateError> handleUnscheduledTrip(FeedScopedId tripId) {
    *
    * @param tripUpdate     GTFS-RT TripUpdate message
    * @param tripDescriptor GTFS-RT TripDescriptor
-   * @return true if successful
+   * @return empty Optional if successful or one containing en error
    */
   private Optional<UpdateError> validateAndHandleModifiedTrip(
     final TripUpdate tripUpdate,
@@ -974,7 +974,7 @@ private Optional<UpdateError> validateAndHandleModifiedTrip(
    * @param tripUpdate  GTFS-RT TripUpdate message
    * @param stops       the stops of each StopTimeUpdate in the TripUpdate message
    * @param serviceDate service date for modified trip
-   * @return true if successful
+   * @return empty Optional if successful or one containing en error
    */
   private Optional<UpdateError> handleModifiedTrip(
     final Trip trip,

src/test/java/org/opentripplanner/common/model/ResultTest.java

@@ -9,7 +9,7 @@ class ResultTest {
 
   @Test
   public void success() {
-    Result<Exception, String> res = Result.success("hello");
+    Result<String, Exception> res = Result.success("hello");
     assertTrue(res.isSuccess());
     assertFalse(res.isFailure());
 
@@ -33,7 +33,7 @@ public void success() {
   @Test
   public void failure() {
     var msg = "An error happened";
-    Result<Exception, String> res = Result.failure(new RuntimeException(msg));
+    Result<String, Exception> res = Result.failure(new RuntimeException(msg));
 
     assertFalse(res.isSuccess());
     assertTrue(res.isFailure());

src/test/java/org/opentripplanner/model/TimetableTest.java

@@ -6,6 +6,7 @@
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.opentripplanner.model.UpdateError.UpdateErrorType.NON_INCREASING_TRIP_TIMES;
 import static org.opentripplanner.model.UpdateError.UpdateErrorType.TRIP_NOT_FOUND_IN_PATTERN;
+import static org.opentripplanner.model.UpdateError.UpdateErrorType.UNKNOWN;
 import static org.opentripplanner.util.TestUtils.AUGUST;
 
 import com.google.transit.realtime.GtfsRealtime.TripDescriptor;
@@ -69,7 +70,7 @@ public void tripNotFoundInPattern() {
     stopTimeUpdateBuilder.setScheduleRelationship(StopTimeUpdate.ScheduleRelationship.NO_DATA);
     var tripUpdate = tripUpdateBuilder.build();
 
-    Result<UpdateError, TripTimesPatch> result = timetable.createUpdatedTripTimes(
+    Result<TripTimesPatch, UpdateError> result = timetable.createUpdatedTripTimes(
       tripUpdate,
       timeZone,
       serviceDate,
@@ -105,6 +106,8 @@ public void badData() {
       BackwardsDelayPropagationType.REQUIRED_NO_DATA
     );
     assertTrue(result.isFailure());
+
+    result.ifFailure(e -> assertEquals(UNKNOWN, e.errorType()));
   }
 
   @Test