[icalendar] optimization of eventfilter-search and more debug output (#9501)

* [icalendar] Optimize searching events and adding a bit debug output

Fixes #9498 by limiting series events when retrieving possible events via
filter.

Adding a bit more debug output to allow debugging the correct scheduling of
events.

Signed-off-by: Michael Wodniok <michi@noorganization.org>

bundles/org.openhab.binding.icalendar/src/main/java/org/openhab/binding/icalendar/internal/handler/ICalendarHandler.java

@@ -266,6 +266,7 @@ public class ICalendarHandler extends BaseBridgeHandler implements CalendarUpdat
      * @return Whether the calendar was loaded successfully.
      */
     private boolean reloadCalendar() {
+        logger.trace("reloading calendar of {}", getThing().getUID());
         if (!calendarFile.isFile()) {
             logger.info("Local file for reloading calendar is missing.");
             return false;
@@ -314,6 +315,7 @@ public class ICalendarHandler extends BaseBridgeHandler implements CalendarUpdat
                 ICalendarHandler.this.updateStates();
                 ICalendarHandler.this.rescheduleCalendarStateUpdate();
             }, currentEvent.end.getEpochSecond() - now.getEpochSecond(), TimeUnit.SECONDS);
+            logger.debug("Scheduled update in {} seconds", currentEvent.end.getEpochSecond() - now.getEpochSecond());
         } else {
             final Event nextEvent = currentCalendar.getNextEvent(now);
             final ICalendarConfiguration currentConfig = this.configuration;
@@ -326,11 +328,14 @@ public class ICalendarHandler extends BaseBridgeHandler implements CalendarUpdat
                 updateJobFuture = scheduler.schedule(() -> {
                     ICalendarHandler.this.rescheduleCalendarStateUpdate();
                 }, 1L, TimeUnit.DAYS);
+                logger.debug("Scheduled reschedule in 1 day");
             } else {
                 updateJobFuture = scheduler.schedule(() -> {
                     ICalendarHandler.this.updateStates();
                     ICalendarHandler.this.rescheduleCalendarStateUpdate();
                 }, nextEvent.start.getEpochSecond() - now.getEpochSecond(), TimeUnit.SECONDS);
+                logger.debug("Scheduled update in {} seconds", nextEvent.start.getEpochSecond() - now.getEpochSecond());
+
             }
         }
     }
@@ -339,6 +344,7 @@ public class ICalendarHandler extends BaseBridgeHandler implements CalendarUpdat
      * Updates the states of the Thing and its channels.
      */
     private void updateStates() {
+        logger.trace("updating states of {}", getThing().getUID());
         final AbstractPresentableCalendar calendar = runtimeCalendar;
         if (calendar == null) {
             updateStatus(ThingStatus.OFFLINE);

bundles/org.openhab.binding.icalendar/src/main/java/org/openhab/binding/icalendar/internal/logic/BiweeklyPresentableCalendar.java

@@ -178,7 +178,7 @@ class BiweeklyPresentableCalendar extends AbstractPresentableCalendar {
     @Override
     public List<Event> getFilteredEventsBetween(Instant begin, Instant end, @Nullable EventTextFilter filter,
             int maximumCount) {
-        List<VEventWPeriod> candidates = this.getVEventWPeriodsBetween(begin, end);
+        List<VEventWPeriod> candidates = this.getVEventWPeriodsBetween(begin, end, maximumCount);
         final List<Event> results = new ArrayList<>(candidates.size());
 
         if (filter != null) {
@@ -237,9 +237,10 @@ class BiweeklyPresentableCalendar extends AbstractPresentableCalendar {
      *
      * @param frameBegin Begin of the frame where to search events.
      * @param frameEnd End of the time frame where to search events.
+     * @param maximumPerSeries Limit the results per series. Set to 0 for no limit.
      * @return All events which begin in the time frame.
      */
-    private List<VEventWPeriod> getVEventWPeriodsBetween(Instant frameBegin, Instant frameEnd) {
+    private List<VEventWPeriod> getVEventWPeriodsBetween(Instant frameBegin, Instant frameEnd, int maximumPerSeries) {
         final List<VEvent> positiveEvents = new ArrayList<>();
         final List<VEvent> negativeEvents = new ArrayList<>();
         classifyEvents(positiveEvents, negativeEvents);
@@ -248,6 +249,7 @@ class BiweeklyPresentableCalendar extends AbstractPresentableCalendar {
         for (final VEvent positiveEvent : positiveEvents) {
             final DateIterator positiveBeginDates = getRecurredEventDateIterator(positiveEvent);
             positiveBeginDates.advanceTo(Date.from(frameBegin));
+            int foundInSeries = 0;
             while (positiveBeginDates.hasNext()) {
                 final Instant begInst = positiveBeginDates.next().toInstant();
                 if (begInst.isAfter(frameEnd)) {
@@ -263,9 +265,17 @@ class BiweeklyPresentableCalendar extends AbstractPresentableCalendar {
                 if (eventUid != null) {
                     if (!isCounteredBy(begInst, eventUid, negativeEvents)) {
                         eventList.add(resultingVEWP);
+                        foundInSeries++;
+                        if (maximumPerSeries != 0 && foundInSeries >= maximumPerSeries) {
+                            break;
+                        }
                     }
                 } else {
                     eventList.add(resultingVEWP);
+                    foundInSeries++;
+                    if (maximumPerSeries != 0 && foundInSeries >= maximumPerSeries) {
+                        break;
+                    }
                 }
             }
         }

bundles/org.openhab.binding.icalendar/src/test/java/org/openhab/binding/icalendar/internal/logic/BiweeklyPresentableCalendarTest.java

@@ -151,6 +151,7 @@ public class BiweeklyPresentableCalendarTest {
      * This test checks for Events that have just begun or ended, and if so it checks for Command Tags
      * and checks if these tags are valid
      */
+    @SuppressWarnings("null")
     @Test
     public void testCommandTagCode() {
         List<Event> events = null;