Merge pull request #490 from IndeedSi/446-fix-dst-overlap-behavior

#446 when dst overlaps, skip duplicate execution only if cron is running less frequent than every hour

Author: jmrozanec

src/main/java/com/cronutils/model/time/SingleExecutionTime.java

@@ -28,7 +28,6 @@
 import com.cronutils.utils.VisibleForTesting;
 
 import java.time.*;
-import java.time.format.DateTimeFormatter;
 import java.time.temporal.ChronoField;
 import java.time.temporal.ChronoUnit;
 import java.time.temporal.TemporalField;
@@ -52,7 +51,6 @@
  * Calculates execution time given a cron pattern.
  */
 public class SingleExecutionTime implements ExecutionTime {
-    private static DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern("yyyyMMddHHmmss");
     private static final int MAX_ITERATIONS = 100_000;
 
     private static final LocalTime MAX_SECONDS = LocalTime.MAX.truncatedTo(SECONDS);
@@ -107,8 +105,15 @@ public Optional<ZonedDateTime> nextExecution(final ZonedDateTime date) {
             if (nextMatch.equals(date)) {
                 nextMatch = nextClosestMatch(date.plusSeconds(1));
 
-                if(nextMatch.format(DATE_TIME_FORMATTER).equals(date.format(DATE_TIME_FORMATTER))){ // daylight saving case: issue #446
-                    nextMatch = nextClosestMatch(date.plusSeconds(1).plusHours(1));
+                if (nextMatch.getOffset().compareTo(date.getOffset()) > 0) {
+                    // daylight saving time overlap case: issue #446
+                    ZonedDateTime nextNextExecution = nextClosestMatch(nextMatch.plusSeconds(1));
+
+                    boolean lessFrequentThan1Hour = (Duration.between(nextMatch, nextNextExecution).toHours() > 1);
+                    if (lessFrequentThan1Hour) {
+                        // Avoid duplicate execution during DST overlap
+                        nextMatch = nextClosestMatch(date.plusSeconds(1).plusHours(1));
+                    }
                 }
             }
             return Optional.of(nextMatch);

src/test/java/com/cronutils/Issue446Test.java

@@ -7,8 +7,9 @@
 import com.cronutils.model.definition.CronDefinitionBuilder;
 import com.cronutils.model.time.ExecutionTime;
 import org.junit.Assert;
-import org.junit.Ignore;
 import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.time.*;
 import java.util.Optional;
@@ -21,6 +22,7 @@
 
 
 public class Issue446Test {
+    private static final Logger LOGGER = LoggerFactory.getLogger(Issue446Test.class);
     private static final CronDefinition definition = CronDefinitionBuilder.defineCron()
             .withMinutes().and()
             .withHours().and()
@@ -38,7 +40,7 @@ public void testWrongIntervalsForEvery6Months() {
         LocalDateTime dayOfApril = LocalDateTime.of(2020, 4, 25, 0, 0);
         Clock clock = Clock.fixed(dayOfApril.toInstant(ZoneOffset.UTC), ZoneId.systemDefault());
         ZonedDateTime dayOfAprilInLocalTimezone = ZonedDateTime.now(clock);
-        System.out.println("now: " + dayOfAprilInLocalTimezone);
+        LOGGER.info("now: " + dayOfAprilInLocalTimezone);
         Cron cron = getEveryMonthFromNow(dayOfAprilInLocalTimezone, 6).instance();
 
         ZonedDateTime nextRun = nextRun(cron, dayOfAprilInLocalTimezone); // first run
@@ -69,7 +71,7 @@ public void testDaylightSavingOverlapMinuteNextRun() {
         LocalDateTime daylightSaving2020 = LocalDateTime.of(2020, 10, 25, 1, 10);
         Clock clock = Clock.fixed(daylightSaving2020.toInstant(ZoneOffset.ofHours(2)),ZoneId.of("Europe/Rome"));
         ZonedDateTime daylightSaving2020InLocalTimezone = ZonedDateTime.now(clock);
-        System.out.println("\nnow: " + daylightSaving2020InLocalTimezone);
+        LOGGER.info("\nnow: " + daylightSaving2020InLocalTimezone);
         Cron cron = getEvery30Minute(daylightSaving2020InLocalTimezone).instance();
 
         ZonedDateTime nextRun = nextRun(cron, daylightSaving2020InLocalTimezone); // first run
@@ -101,13 +103,11 @@ public void testDaylightSavingOverlapMinuteNextRun() {
     }
 
     @Test
-    @Ignore
     public void testDaylightSavingOverlapHourNextRun() {
-
         LocalDateTime startDay = LocalDateTime.of(2020, 10, 24, 1, 0); // Day before Daylight saving
-        Clock clock = Clock.fixed(startDay.toInstant(ZoneOffset.ofHours(2)),ZoneId.of("Europe/Rome"));
+        Clock clock = Clock.fixed(startDay.toInstant(ZoneOffset.ofHours(2)), ZoneId.of("Europe/Rome"));
         ZonedDateTime daylightSaving2020InLocalTimezone = ZonedDateTime.now(clock);
-        System.out.println("\nnow: " + daylightSaving2020InLocalTimezone);
+        LOGGER.info("\nnow: " + daylightSaving2020InLocalTimezone);
         Cron cron = getEveryHour(daylightSaving2020InLocalTimezone).instance();
 
         ZonedDateTime nextRun = nextRun(cron, daylightSaving2020InLocalTimezone);
@@ -120,9 +120,9 @@ public void testDaylightSavingOverlapHourNextRun() {
         Assert.assertEquals(ZoneOffset.ofHours(2), nextRun.getOffset());
 
         startDay = LocalDateTime.of(2020, 10, 25, 1, 0); // Daylight saving
-        clock = Clock.fixed(startDay.toInstant(ZoneOffset.ofHours(2)),ZoneId.of("Europe/Rome"));
+        clock = Clock.fixed(startDay.toInstant(ZoneOffset.ofHours(2)), ZoneId.of("Europe/Rome"));
         daylightSaving2020InLocalTimezone = ZonedDateTime.now(clock);
-        System.out.println("\nnow: " + daylightSaving2020InLocalTimezone);
+        LOGGER.info("\nnow: " + daylightSaving2020InLocalTimezone);
         cron = getEveryHour(daylightSaving2020InLocalTimezone).instance();
 
         nextRun = nextRun(cron, daylightSaving2020InLocalTimezone); // first run
@@ -167,7 +167,7 @@ private static ZonedDateTime nextRun(Cron cron, ZonedDateTime when) {
         if (!next.isPresent()) {
             fail();
         }
-        System.out.println("Calculated next run at " + next.get());
+        LOGGER.info("Calculated next run at " + next.get());
         return next.get();
     }
 }