org.opentripplanner.updater.trip.TimetableSnapshotManager Maven / Gradle / Ivy
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package org.opentripplanner.updater.trip;
import java.time.LocalDate;
import java.util.Objects;
import java.util.function.Supplier;
import javax.annotation.Nullable;
import org.opentripplanner.model.RealTimeTripUpdate;
import org.opentripplanner.model.Timetable;
import org.opentripplanner.model.TimetableSnapshot;
import org.opentripplanner.routing.algorithm.raptoradapter.transit.mappers.TransitLayerUpdater;
import org.opentripplanner.routing.util.ConcurrentPublished;
import org.opentripplanner.transit.model.framework.FeedScopedId;
import org.opentripplanner.transit.model.framework.Result;
import org.opentripplanner.transit.model.network.TripPattern;
import org.opentripplanner.updater.TimetableSnapshotSourceParameters;
import org.opentripplanner.updater.spi.UpdateError;
import org.opentripplanner.updater.spi.UpdateSuccess;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A class which abstracts away locking, updating, committing and purging of the timetable snapshot.
* In order to keep code reviews easier this is an intermediate stage and will be refactored further.
* In particular the following refactorings are planned:
*
* - create only one "snapshot manager" per transit model that is shared between Siri/GTFS-RT updaters
*/
public final class TimetableSnapshotManager {
private static final Logger LOG = LoggerFactory.getLogger(TimetableSnapshotManager.class);
private final TransitLayerUpdater transitLayerUpdater;
/**
* The working copy of the timetable snapshot. Should not be visible to routing threads.
* By design, only one thread should ever be writing to this buffer.
*/
private final TimetableSnapshot buffer = new TimetableSnapshot();
/**
* The last committed snapshot that was handed off to a routing thread. This snapshot may be given
* to more than one routing thread.
*/
private final ConcurrentPublished snapshot = new ConcurrentPublished<>();
/**
* Should expired real-time data be purged from the graph.
* TODO RT_AB: Clarify exactly what "purge" means and in what circumstances would one turn it off.
*/
private final boolean purgeExpiredData;
/**
* We inject a provider to retrieve the current service-date(now). This enables us to unit-test
* the purgeExpiredData feature.
*/
private final Supplier localDateNow;
private LocalDate lastPurgeDate = null;
/**
*
* @param localDateNow This supplier allows you to inject a custom lambda to override what is
* considered 'today'. This is useful for unit testing.
*/
public TimetableSnapshotManager(
TransitLayerUpdater transitLayerUpdater,
TimetableSnapshotSourceParameters parameters,
Supplier localDateNow
) {
this.transitLayerUpdater = transitLayerUpdater;
this.purgeExpiredData = parameters.purgeExpiredData();
this.localDateNow = Objects.requireNonNull(localDateNow);
// Force commit so that snapshot initializes
commitTimetableSnapshot(true);
}
/**
* @return an up-to-date snapshot mapping TripPatterns to Timetables. This snapshot and the
* timetable objects it references are guaranteed to never change, so the requesting thread is
* provided a consistent view of all TripTimes. The routing thread need only release its reference
* to the snapshot to release resources.
*/
public TimetableSnapshot getTimetableSnapshot() {
return snapshot.get();
}
/**
* @return the current timetable snapshot buffer that contains pending changes (not yet published
* in a snapshot).
* This should be used in the context of an updater to build a TransitEditorService that sees all
* the changes applied so far by real-time updates.
*/
public TimetableSnapshot getTimetableSnapshotBuffer() {
return buffer;
}
/**
* Request a commit of the timetable snapshot.
*
* If there are no updates buffered up or not enough time has elapsed, the existing snapshot
* is returned.
*
* @param force Force the committing of a new snapshot even if the above conditions are not met.
*/
void commitTimetableSnapshot(final boolean force) {
if (force || buffer.isDirty()) {
LOG.debug("Committing {}", buffer);
snapshot.publish(buffer.commit(transitLayerUpdater, force));
} else {
LOG.debug("Buffer was unchanged, keeping old snapshot.");
}
}
/**
* Get the current trip pattern given a trip id and a service date, if it has been changed from
* the scheduled pattern with an update, for which the stopPattern is different.
*
* @param tripId trip id
* @param serviceDate service date
* @return trip pattern created by the updater; null if pattern has not been changed for this trip.
*/
@Nullable
public TripPattern getRealtimeAddedTripPattern(FeedScopedId tripId, LocalDate serviceDate) {
return buffer.getRealtimeAddedTripPattern(tripId, serviceDate);
}
/**
* Make a snapshot after each message in anticipation of incoming requests.
* Purge data if necessary (and force new snapshot if anything was purged).
* Make sure that the public (locking) getTimetableSnapshot function is not called.
*/
public void purgeAndCommit() {
if (purgeExpiredData) {
final boolean modified = purgeExpiredData();
commitTimetableSnapshot(modified);
} else {
commitTimetableSnapshot(false);
}
}
/**
* If a previous realtime update has changed which trip pattern is associated with the given trip
* on the given service date, this method will dissociate the trip from that pattern and remove
* the trip's timetables from that pattern on that particular service date.
*
* For this service date, the trip will revert to its original trip pattern from the scheduled
* data, remaining on that pattern unless it's changed again by a future realtime update.
*/
public void revertTripToScheduledTripPattern(FeedScopedId tripId, LocalDate serviceDate) {
buffer.revertTripToScheduledTripPattern(tripId, serviceDate);
}
/**
* Remove realtime data from previous service dates from the snapshot. This is useful so that
* instances that run for multiple days don't accumulate a lot of realtime data for past
* dates which would increase memory consumption.
* If your OTP instances are restarted throughout the day, this is less useful and can be
* turned off.
*
* @return true if any data has been modified and false if no purging has happened.
*/
private boolean purgeExpiredData() {
final LocalDate today = localDateNow.get();
// TODO: Base this on numberOfDaysOfLongestTrip for tripPatterns
final LocalDate previously = today.minusDays(2); // Just to be safe...
// Purge data only if we have changed date
if (lastPurgeDate != null && lastPurgeDate.compareTo(previously) >= 0) {
return false;
}
LOG.debug("Purging expired realtime data");
lastPurgeDate = previously;
return buffer.purgeExpiredData(previously);
}
/**
* Clear all data of snapshot for the provided feed id
*/
public void clearBuffer(String feedId) {
buffer.clear(feedId);
}
/**
* Update the TripTimes of one Trip in a Timetable of a TripPattern. If the Trip of the TripTimes
* does not exist yet in the Timetable, add it. This method will make a protective copy of the
* Timetable if such a copy has not already been made while building up this snapshot, handling
* both cases where patterns were pre-existing in static data or created by realtime data.
*
* @return whether the update was actually applied
*/
public Result updateBuffer(RealTimeTripUpdate realTimeTripUpdate) {
return buffer.update(realTimeTripUpdate);
}
/**
* Returns an updated timetable for the specified pattern if one is available in this snapshot, or
* the originally scheduled timetable if there are no updates in this snapshot.
*/
public Timetable resolve(TripPattern pattern, LocalDate serviceDate) {
return buffer.resolve(pattern, serviceDate);
}
}