OO-561: check if there is an ical4j time zone available before using it

src/main/java/org/olat/commons/calendar/CalendarModule.java

@@ -26,6 +26,8 @@ import net.fortuna.ical4j.util.CompatibilityHints;
 
 import org.olat.core.configuration.AbstractOLATModule;
 import org.olat.core.configuration.PersistedProperties;
+import org.olat.core.logging.OLog;
+import org.olat.core.logging.Tracing;
 
 /**
  * 
@@ -38,6 +40,8 @@ import org.olat.core.configuration.PersistedProperties;
  */
 public class CalendarModule extends AbstractOLATModule {
 	
+	private static final OLog log = Tracing.createLoggerFor(CalendarModule.class);
+	
 	private TimeZone defaultTimeZone;
 	private TimeZoneRegistry timeZoneRegistry;
 	
@@ -48,8 +52,12 @@ public class CalendarModule extends AbstractOLATModule {
 		System.setProperty(CompatibilityHints.KEY_RELAXED_UNFOLDING, "true");
 		System.setProperty(CompatibilityHints.KEY_RELAXED_PARSING, "true");
 		String defaultTimeZoneID = java.util.TimeZone.getDefault().getID();
+		log.info("Calendar time zone: " + defaultTimeZoneID);
 		timeZoneRegistry = TimeZoneRegistryFactory.getInstance().createRegistry();
 		defaultTimeZone = timeZoneRegistry.getTimeZone(defaultTimeZoneID);
+		if(defaultTimeZone == null) {
+			log.error("Cannot match the JVM default time zone to an ical4j time zone: " + defaultTimeZoneID);
+		}
 	}
 
 	@Override

src/main/java/org/olat/commons/calendar/CalendarUtils.java

@@ -205,7 +205,9 @@ public class CalendarUtils {
 				Date dUntil = recur.getUntil();
 				DateTime dtUntil = dUntil == null ? null : new DateTime(dUntil.getTime());
 				if(dtUntil != null) {
-					dtUntil.setTimeZone(tz);
+					if(tz != null) {
+						dtUntil.setTimeZone(tz);
+					}
 					return dtUntil;
 				}
 			} catch (ParseException e) {
@@ -245,7 +247,9 @@ public class CalendarUtils {
 			}
 			if(recurrenceEnd != null) {
 				DateTime recurEndDT = new DateTime(recurrenceEnd.getTime());
-				recurEndDT.setTimeZone(tz);
+				if(tz != null) {
+					recurEndDT.setTimeZone(tz);
+				}
 				sb.append(";");
 				sb.append(KalendarEvent.UNTIL);
 				sb.append("=");

src/main/java/org/olat/commons/calendar/ICalFileCalendarManager.java

@@ -63,7 +63,6 @@ import net.fortuna.ical4j.model.property.CalScale;
 import net.fortuna.ical4j.model.property.Clazz;
 import net.fortuna.ical4j.model.property.Contact;
 import net.fortuna.ical4j.model.property.Created;
-import net.fortuna.ical4j.model.property.DtEnd;
 import net.fortuna.ical4j.model.property.Duration;
 import net.fortuna.ical4j.model.property.ExDate;
 import net.fortuna.ical4j.model.property.LastModified;
@@ -353,9 +352,13 @@ public class ICalFileCalendarManager extends BasicManager implements CalendarMan
 		if (!kEvent.isAllDayEvent()) {
 			// regular VEvent
 			DateTime dtBegin = new DateTime(kEvent.getBegin());
-			dtBegin.setTimeZone(tz);
+			if(tz != null) {
+				dtBegin.setTimeZone(tz);
+			}
 			DateTime dtEnd = new DateTime(kEvent.getEnd());
-			dtEnd.setTimeZone(tz);
+			if(tz != null) {
+				dtEnd.setTimeZone(tz);
+			}
 			vEvent = new VEvent(dtBegin, dtEnd, kEvent.getSubject());
 		} else {
 			// AllDay VEvent
@@ -707,7 +710,11 @@ public class ICalFileCalendarManager extends BasicManager implements CalendarMan
 			
 			java.util.Calendar recurStartCal = java.util.Calendar.getInstance();
 			recurStartCal.clear();
-			recurStartCal.setTimeInMillis(date.getTime()-tz.getOffset(date.getTime()));
+			if(tz == null) {
+				recurStartCal.setTimeInMillis(date.getTime());
+			} else {
+				recurStartCal.setTimeInMillis(date.getTime() - tz.getOffset(date.getTime()));
+			}
 			long duration = kEvent.getEnd().getTime() - kEvent.getBegin().getTime();
 
 			java.util.Calendar beginCal = java.util.Calendar.getInstance();