Merge pull request #717 from focus-shift/find-weekday-between-improve…

…ments

Replace interator with Stream interation over localdates

jollyday-core/src/main/java/de/focus_shift/jollyday/core/parser/functions/FindWeekDayBetween.java

@@ -3,16 +3,12 @@
 import de.focus_shift.jollyday.core.spi.FixedWeekdayBetweenFixed;
 
 import java.time.LocalDate;
-import java.util.Iterator;
-import java.util.NoSuchElementException;
 import java.util.function.Function;
-import java.util.stream.StreamSupport;
+import java.util.stream.Stream;
 
-import static java.util.Spliterator.IMMUTABLE;
-import static java.util.Spliterator.ORDERED;
-import static java.util.Spliterators.spliteratorUnknownSize;
+import static java.time.temporal.ChronoUnit.DAYS;
 
-public class FindWeekDayBetween implements Function<FixedWeekdayBetweenFixed, LocalDate>, Iterable<LocalDate> {
+public class FindWeekDayBetween implements Function<FixedWeekdayBetweenFixed, LocalDate> {
 
   private final LocalDate from;
   private final LocalDate to;
@@ -24,40 +20,9 @@ public FindWeekDayBetween(final LocalDate from, final LocalDate to) {
 
   @Override
   public LocalDate apply(final FixedWeekdayBetweenFixed fwm) {
-    return StreamSupport.stream(spliteratorUnknownSize(iterator(), ORDERED | IMMUTABLE), false)
+    return Stream.iterate(from, date -> date.plusDays(1))
+      .limit(DAYS.between(from, to) + 1)
       .filter(date -> date.getDayOfWeek() == fwm.weekday())
       .findFirst().orElse(null);
   }
-
-  @Override
-  public Iterator<LocalDate> iterator() {
-    return new FindWeekDayBetweenIterator(from, to);
-  }
-
-  private static final class FindWeekDayBetweenIterator implements Iterator<LocalDate> {
-
-    private LocalDate cursor;
-    private final LocalDate endDate;
-
-    FindWeekDayBetweenIterator(final LocalDate startDate, final LocalDate endDate) {
-      this.cursor = startDate;
-      this.endDate = endDate;
-    }
-
-    @Override
-    public boolean hasNext() {
-      return cursor.isBefore(endDate) || cursor.isEqual(endDate);
-    }
-
-    @Override
-    public LocalDate next() {
-      if (!hasNext()) {
-        throw new NoSuchElementException("next date is after endDate which is not in range anymore.");
-      }
-
-      final LocalDate current = cursor;
-      cursor = cursor.plusDays(1);
-      return current;
-    }
-  }
 }

jollyday-core/src/test/java/de/focus_shift/jollyday/core/parser/functions/FindWeekDayBetweenTest.java

@@ -0,0 +1,85 @@
+package de.focus_shift.jollyday.core.parser.functions;
+
+
+import de.focus_shift.jollyday.core.HolidayType;
+import de.focus_shift.jollyday.core.spi.Fixed;
+import de.focus_shift.jollyday.core.spi.FixedWeekdayBetweenFixed;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+import java.time.DayOfWeek;
+import java.time.LocalDate;
+import java.time.Year;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class FindWeekDayBetweenTest {
+
+  @ParameterizedTest
+  @CsvSource({
+    "MONDAY,2025-01-06",
+    "WEDNESDAY,2025-01-08",
+    "FRIDAY,2025-01-10",
+  })
+  void ensureToFindFirstWeekdayBetweenTwoFixedDates(final DayOfWeek dayOfWeek, final LocalDate expectedDate) {
+    final LocalDate firstMonday = LocalDate.of(2025, 1, 6);
+    final LocalDate secondFriday = LocalDate.of(2025, 1, 17);
+    final LocalDate actualDate = new FindWeekDayBetween(firstMonday, secondFriday).apply(getFixedWeekdayBetweenFixed(dayOfWeek));
+    assertThat(actualDate).isEqualTo(expectedDate);
+  }
+
+  @Test
+  void ensureToReturnNullIfNoWeekdayWasFound() {
+    final LocalDate monday = LocalDate.of(2025, 1, 6);
+    final LocalDate tuesday = LocalDate.of(2025, 1, 7);
+    final LocalDate actualDate = new FindWeekDayBetween(monday, tuesday).apply(getFixedWeekdayBetweenFixed(DayOfWeek.WEDNESDAY));
+    assertThat(actualDate).isNull();
+  }
+
+  private static FixedWeekdayBetweenFixed getFixedWeekdayBetweenFixed(final DayOfWeek dayOfWeek) {
+
+    return new FixedWeekdayBetweenFixed() {
+
+      @Override
+      public Fixed from() {
+        return null;
+      }
+
+      @Override
+      public Fixed to() {
+        return null;
+      }
+
+      @Override
+      public DayOfWeek weekday() {
+        return dayOfWeek;
+      }
+
+      @Override
+      public String descriptionPropertiesKey() {
+        return "";
+      }
+
+      @Override
+      public HolidayType holidayType() {
+        return null;
+      }
+
+      @Override
+      public Year validFrom() {
+        return null;
+      }
+
+      @Override
+      public Year validTo() {
+        return null;
+      }
+
+      @Override
+      public YearCycle cycle() {
+        return null;
+      }
+    };
+  }
+}