Merge pull request #453 from IndeedSi/402-fix-every-x-years-behavior

#402 Fix every x years behavior by checking offset in range and correcting previous value calculation in EveryFieldValueGenerator

Author: jmrozanec

src/main/java/com/cronutils/model/time/generator/EveryFieldValueGenerator.java

@@ -86,8 +86,14 @@ private int getNext(int reference, Every every) {
     @Override
     public int generatePreviousValue(final int reference) throws NoSuchValueException {
         final Every every = (Every) cronField.getExpression();
+        if (reference < from) {
+            throw new NoSuchValueException();
+        }
+        if (reference > to) {
+            return to;
+        }
         final int period = every.getPeriod().getValue();
-        final int remainder = reference % period;
+        final int remainder = (reference - from) % period;
         if (remainder == 0) {
             return reference - period;
         } else {
@@ -100,7 +106,7 @@ protected List<Integer> generateCandidatesNotIncludingIntervalExtremes(final int
         final List<Integer> values = new ArrayList<>();
         try {
             final int offset = offset();
-            if (start != offset) {
+            if (start < offset && offset < end) {
                 values.add(offset);
             }
             int reference = generateNextValue(start);

src/test/java/com/cronutils/Issue402Test.java

@@ -44,6 +44,7 @@
 import static com.cronutils.model.CronType.QUARTZ;
 import static java.time.ZoneOffset.UTC;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
@@ -842,6 +843,49 @@ public void testLastExecutionIssue312() {
         }
     }
 
+    /**
+     * Issue #402
+     * https://github.com/jmrozanec/cron-utils/issues/402
+     * Fix last and next execution time when using every X years
+     */
+    @Test
+    public void testLastExecutionIssue402() {
+        // Every 2 years at March 1st midnight
+        ExecutionTime execution = ExecutionTime.forCron(parser.parse("0 0 0 1 3 ? 2001-2020/2"));
+
+        ZonedDateTime currentDateTime = ZonedDateTime.of(LocalDate.of(2015, 1, 15), LocalTime.MIDNIGHT, ZoneOffset.UTC);
+        // Check next execution time is correct
+        Optional<ZonedDateTime> nextExecution = execution.nextExecution(currentDateTime);
+        assertTrue(nextExecution.isPresent());
+        assertEquals(ZonedDateTime.of(LocalDate.of(2015, 3, 1), LocalTime.MIDNIGHT, ZoneOffset.UTC), nextExecution.get());
+        // Check previous execution time is correct
+        Optional<ZonedDateTime> lastExecution = execution.lastExecution(currentDateTime);
+        assertTrue(lastExecution.isPresent());
+        assertEquals(ZonedDateTime.of(LocalDate.of(2013, 3, 1), LocalTime.MIDNIGHT, ZoneOffset.UTC), lastExecution.get());
+
+        lastExecution = execution.lastExecution(nextExecution.get());
+        assertTrue(lastExecution.isPresent());
+        assertEquals(ZonedDateTime.of(LocalDate.of(2013, 3, 1), LocalTime.MIDNIGHT, ZoneOffset.UTC), lastExecution.get());
+
+        // Assume the current time is before the start time of every expression, check last and next execution.ß
+        ZonedDateTime timeBeforeStart = ZonedDateTime.of(LocalDate.of(1996, 1, 15), LocalTime.MIDNIGHT, ZoneOffset.UTC);
+        Optional<ZonedDateTime> nextBeforeStart = execution.nextExecution(timeBeforeStart);
+        assertTrue(nextBeforeStart.isPresent());
+        assertEquals(ZonedDateTime.of(LocalDate.of(2001, 3, 1), LocalTime.MIDNIGHT, ZoneOffset.UTC), nextBeforeStart.get());
+
+        Optional<ZonedDateTime> lastBeforeStart = execution.lastExecution(nextBeforeStart.get());
+        assertFalse(lastBeforeStart.isPresent());
+
+        // Assume the current time is before the start time of every expression, check last and next execution.ß
+        ZonedDateTime timeAfterEnd = ZonedDateTime.of(LocalDate.of(2025, 1, 15), LocalTime.MIDNIGHT, ZoneOffset.UTC);
+        Optional<ZonedDateTime> nextAfterEnd = execution.nextExecution(timeAfterEnd);
+        assertFalse(nextAfterEnd.isPresent());
+
+        Optional<ZonedDateTime> lastAfterEnd = execution.lastExecution(timeAfterEnd);
+        assertTrue(lastAfterEnd.isPresent());
+        assertEquals(ZonedDateTime.of(LocalDate.of(2019, 3, 1), LocalTime.MIDNIGHT, ZoneOffset.UTC), lastAfterEnd.get());
+    }
+
     /**
      * Issue #424
      * https://github.com/jmrozanec/cron-utils/issues/424