BAEL-924: How to get all LocalDates between two dates? (#2012)

core-java-9/src/main/java/com/baeldung/java9/time/TimeApi.java

@@ -0,0 +1,44 @@
+package com.baeldung.java9.time;
+
+import java.time.LocalDate;
+import java.time.temporal.ChronoUnit;
+import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.GregorianCalendar;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class TimeApi {
+
+    public static List<Date> getDatesBetweenUsingJava7(Date startDate, Date endDate) {
+        List<Date> datesInRange = new ArrayList<Date>();
+        Calendar calendar = new GregorianCalendar();
+        calendar.setTime(startDate);
+
+        Calendar endCalendar = new GregorianCalendar();
+        endCalendar.setTime(endDate);
+
+        while (calendar.before(endCalendar)) {
+            Date result = calendar.getTime();
+            datesInRange.add(result);
+            calendar.add(Calendar.DATE, 1);
+        }
+        return datesInRange;
+    }
+
+    public static List<LocalDate> getDatesBetweenUsingJava8(LocalDate startDate, LocalDate endDate) {
+        List<LocalDate> datesInRange = new ArrayList<LocalDate>();
+        long numOfDaysBetween = ChronoUnit.DAYS.between(startDate, endDate);
+        Stream.iterate(0, i -> i + 1).limit(numOfDaysBetween).forEach(i -> {
+            datesInRange.add(startDate.plusDays(i));
+        });
+        return datesInRange;
+    }
+
+    public static List<LocalDate> getDatesBetweenUsingJava9(LocalDate startDate, LocalDate endDate) {
+        return startDate.datesUntil(endDate).collect(Collectors.toList());
+    }
+
+}

core-java-9/src/test/java/com/baeldung/java9/time/TimeApiTest.java

@@ -0,0 +1,66 @@
+package com.baeldung.java9.time;
+
+import java.time.LocalDate;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+public class TimeApiTest {
+
+    @Test
+    public void givenGetDatesBetweenWithUsingJava7_WhenStartEndDate_thenDatesList() {
+        Date startDate = Calendar.getInstance().getTime();
+        Calendar endCalendar = Calendar.getInstance();
+        endCalendar.add(Calendar.DATE, 3);
+        Date endDate = endCalendar.getTime();
+
+        List<Date> dates = TimeApi.getDatesBetweenUsingJava7(startDate, endDate);
+        assertEquals(dates.size(), 3);
+
+        Calendar calendar = Calendar.getInstance();
+        Date date1 = calendar.getTime();
+        assertEquals(dates.get(0).getDay(), date1.getDay());
+        assertEquals(dates.get(0).getMonth(), date1.getMonth());
+        assertEquals(dates.get(0).getYear(), date1.getYear());
+
+        calendar.add(Calendar.DATE, 1);
+        Date date2 = calendar.getTime();
+        assertEquals(dates.get(1).getDay(), date2.getDay());
+        assertEquals(dates.get(1).getMonth(), date2.getMonth());
+        assertEquals(dates.get(1).getYear(), date2.getYear());
+
+        calendar.add(Calendar.DATE, 1);
+        Date date3 = calendar.getTime();
+        assertEquals(dates.get(2).getDay(), date3.getDay());
+        assertEquals(dates.get(2).getMonth(), date3.getMonth());
+        assertEquals(dates.get(2).getYear(), date3.getYear());
+    }
+
+    @Test
+    public void givenGetDatesBetweenWithUsingJava8_WhenStartEndDate_thenDatesList() {
+        LocalDate startDate = LocalDate.now();
+        LocalDate endDate = LocalDate.now().plusDays(3);
+
+        List<LocalDate> dates = TimeApi.getDatesBetweenUsingJava8(startDate, endDate);
+        assertEquals(dates.size(), 3);
+        assertEquals(dates.get(0), LocalDate.now());
+        assertEquals(dates.get(1), LocalDate.now().plusDays(1));
+        assertEquals(dates.get(2), LocalDate.now().plusDays(2));
+    }
+
+    @Test
+    public void givenGetDatesBetweenWithUsingJava9_WhenStartEndDate_thenDatesList() {
+        LocalDate startDate = LocalDate.now();
+        LocalDate endDate = LocalDate.now().plusDays(3);
+
+        List<LocalDate> dates = TimeApi.getDatesBetweenUsingJava9(startDate, endDate);
+        assertEquals(dates.size(), 3);
+        assertEquals(dates.get(0), LocalDate.now());
+        assertEquals(dates.get(1), LocalDate.now().plusDays(1));
+        assertEquals(dates.get(2), LocalDate.now().plusDays(2));
+    }
+
+}