BAEL-3140: Comparing Dates in Java - examples.

java-dates-2/pom.xml

@@ -20,7 +20,13 @@
             <artifactId>joda-time</artifactId>
             <version>${joda-time.version}</version>
         </dependency>
-
+
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+
         <!-- https://mvnrepository.com/artifact/commons-validator/commons-validator -->
         <dependency>
             <groupId>commons-validator</groupId>
@@ -63,6 +69,7 @@
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>
         <joda-time.version>2.10</joda-time.version>
+        <commons-lang3.version>3.9</commons-lang3.version>
         <commons-validator.version>1.6</commons-validator.version>
         <maven.compiler.source>1.9</maven.compiler.source>
         <maven.compiler.target>1.9</maven.compiler.target>

java-dates-2/src/main/java/com/baeldung/date/comparison/DateTimeComparisonUtils.java

@@ -0,0 +1,35 @@
+package com.baeldung.date.comparison;
+
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+
+import static java.time.temporal.ChronoUnit.*;
+
+public class DateTimeComparisonUtils {
+
+    public static boolean isSameDay(LocalDateTime timestamp, LocalDate localDateToCompare) {
+        return timestamp.toLocalDate().isEqual(localDateToCompare);
+    }
+
+    public static boolean isSameDay(LocalDateTime timestamp, LocalDateTime timestampToCompare) {
+        return timestamp.truncatedTo(DAYS).isEqual(timestampToCompare.truncatedTo(DAYS));
+    }
+
+    public static boolean isSameHour(LocalDateTime timestamp, LocalDateTime timestampToCompare) {
+        return timestamp.truncatedTo(HOURS).isEqual(timestampToCompare.truncatedTo(HOURS));
+    }
+
+    public static boolean isSameMinute(LocalDateTime timestamp, LocalDateTime timestampToCompare) {
+        return timestamp.truncatedTo(MINUTES).isEqual(timestampToCompare.truncatedTo(MINUTES));
+    }
+
+    public static boolean isSameHour(ZonedDateTime zonedTimestamp, ZonedDateTime zonedTimestampToCompare) {
+        return zonedTimestamp.truncatedTo(HOURS).isEqual(zonedTimestampToCompare.truncatedTo(HOURS));
+    }
+
+    public static boolean isSameHour(ZonedDateTime zonedDateTime, LocalDateTime localDateTime, ZoneId zoneId) {
+        return isSameHour(zonedDateTime, localDateTime.atZone(zoneId));
+    }
+}

java-dates-2/src/main/java/com/baeldung/date/comparison/LegacyDateComparisonUtils.java

@@ -0,0 +1,17 @@
+package com.baeldung.date.comparison;
+
+import org.apache.commons.lang3.time.DateUtils;
+
+import java.util.Calendar;
+import java.util.Date;
+
+public class LegacyDateComparisonUtils {
+
+    public static boolean isSameDay(Date date, Date dateToCompare) {
+        return DateUtils.isSameDay(date, dateToCompare);
+    }
+
+    public static boolean isSameHour(Date date, Date dateToCompare) {
+        return DateUtils.truncatedEquals(date, dateToCompare, Calendar.HOUR);
+    }
+}

java-dates-2/src/test/java/com/baeldung/date/comparison/DateTimeComparisonUtilsUnitTest.java

@@ -0,0 +1,75 @@
+package com.baeldung.date.comparison;
+
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThat;
+
+class DateTimeComparisonUtilsUnitTest {
+
+    @Test
+    void givenLocalDateTimes_whenIsSameDay_thenCompareTrue() {
+        LocalDateTime firstTimestamp = LocalDateTime.of(2019, 8, 10, 11, 00, 0);
+        LocalDateTime secondTimestamp = firstTimestamp.plusHours(5);
+        LocalDateTime thirdTimestamp = firstTimestamp.plusDays(1);
+
+        assertThat(DateTimeComparisonUtils.isSameDay(firstTimestamp, secondTimestamp), is(true));
+
+        assertThat(DateTimeComparisonUtils.isSameDay(secondTimestamp, thirdTimestamp), is(false));
+    }
+
+    @Test
+    void givenLocalDateAndLocalDateTime_whenIsSameDay_thenCompareTrue() {
+        LocalDate localDate = LocalDate.of(2019, 8, 10);
+        LocalDateTime localDateTime = LocalDateTime.of(2019, 8, 10, 11, 30, 0);
+
+        assertThat(DateTimeComparisonUtils.isSameDay(localDateTime, localDate), is(true));
+    }
+
+    @Test
+    void givenLocalDateTimes_whenIsSameHour_thenCompareTrue() {
+        LocalDateTime firstTimestamp = LocalDateTime.of(2019, 8, 10, 8, 00, 0);
+        LocalDateTime secondTimestamp = firstTimestamp.plusMinutes(15);
+        LocalDateTime thirdTimestamp = firstTimestamp.plusHours(2);
+
+        assertThat(DateTimeComparisonUtils.isSameHour(firstTimestamp, secondTimestamp), is(true));
+
+        assertThat(DateTimeComparisonUtils.isSameHour(secondTimestamp, thirdTimestamp), is(false));
+    }
+
+    @Test
+    void givenLocalDateTimes_whenIsSameMinute_thenCompareTrue() {
+        LocalDateTime firstTimestamp = LocalDateTime.of(2019, 8, 10, 8, 15, 0);
+        LocalDateTime secondTimestamp = firstTimestamp.plusSeconds(30);
+        LocalDateTime thirdTimestamp = firstTimestamp.plusMinutes(5);
+
+        assertThat(DateTimeComparisonUtils.isSameMinute(firstTimestamp, secondTimestamp), is(true));
+
+        assertThat(DateTimeComparisonUtils.isSameMinute(secondTimestamp, thirdTimestamp), is(false));
+    }
+
+    @Test
+    void givenZonedDateTimes_whenIsSameHour_thenCompareTrue() {
+        ZonedDateTime zonedTimestamp = ZonedDateTime.of(2019, 8, 10, 8, 0, 0, 30,
+          ZoneId.of("America/New_York"));
+        ZonedDateTime zonedTimestampToCompare = ZonedDateTime.of(2019, 8, 10, 14, 0, 0, 0,
+          ZoneId.of("Europe/Berlin"));
+
+        assertThat(DateTimeComparisonUtils.isSameHour(zonedTimestamp, zonedTimestampToCompare), is(true));
+    }
+
+    @Test
+    void givenZonedDateTimeAndLocalDateTime_whenIsSameHour_thenCompareTrue() {
+        ZonedDateTime zonedTimestamp = ZonedDateTime.of(2019, 8, 10, 8, 15, 0, 0,
+          ZoneId.of("America/New_York"));
+        LocalDateTime localTimestamp = LocalDateTime.of(2019, 8, 10, 14, 20, 0);
+        ZoneId zoneId = ZoneId.of("Europe/Berlin");
+
+        assertThat(DateTimeComparisonUtils.isSameHour(zonedTimestamp, localTimestamp, zoneId), is(true));
+    }
+}

java-dates-2/src/test/java/com/baeldung/date/comparison/Java8DateTimeApiGeneralComparisonsUnitTest.java

@@ -0,0 +1,83 @@
+package com.baeldung.date.comparison;
+
+import org.junit.Test;
+
+import java.time.*;
+
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThat;
+
+public class Java8DateTimeApiGeneralComparisonsUnitTest {
+
+    @Test
+    public void givenLocalDates_whenComparing_thenAssertsPass() {
+        LocalDate firstDate = LocalDate.of(2019, 8, 10);
+        LocalDate secondDate = LocalDate.of(2019, 7, 1);
+        LocalDate thirdDate = LocalDate.of(2019, 7, 1); // same date as secondDate
+
+        assertThat(firstDate.isAfter(secondDate), is(true));
+        assertThat(firstDate.isBefore(secondDate), is(false));
+
+        assertThat(firstDate.isEqual(secondDate), is(false));
+        assertThat(firstDate.equals(secondDate), is(false));
+
+        assertThat(firstDate.compareTo(secondDate), is(1));
+        assertThat(secondDate.compareTo(firstDate), is(-1));
+
+        assertThat(secondDate.isAfter(thirdDate), is(false));
+        assertThat(secondDate.isBefore(thirdDate), is(false));
+        assertThat(secondDate.isEqual(thirdDate), is(true));
+        assertThat(secondDate.equals(thirdDate), is(true));
+        assertThat(secondDate.compareTo(thirdDate), is(0));
+    }
+
+    @Test
+    public void givenLocalDateTimes_whenComparing_thenAssertsPass() {
+        LocalDateTime firstTimestamp = LocalDateTime.of(2019, 8, 10, 11, 30, 0);
+        LocalDateTime secondTimestamp = LocalDateTime.of(2019, 8, 10, 11, 15, 0);
+        LocalDateTime thirdTimestamp = LocalDateTime.of(2019, 8, 10, 11, 15, 0); // same as secondTimestamp
+
+        assertThat(firstTimestamp.isAfter(secondTimestamp), is(true));
+        assertThat(firstTimestamp.isBefore(secondTimestamp), is(false));
+
+        assertThat(firstTimestamp.isEqual(secondTimestamp), is(false));
+        assertThat(firstTimestamp.equals(secondTimestamp), is(false));
+
+        assertThat(firstTimestamp.compareTo(secondTimestamp), is(1));
+        assertThat(secondTimestamp.compareTo(firstTimestamp), is(-1));
+
+        assertThat(secondTimestamp.isAfter(thirdTimestamp), is(false));
+        assertThat(secondTimestamp.isBefore(thirdTimestamp), is(false));
+        assertThat(secondTimestamp.isEqual(thirdTimestamp), is(true));
+        assertThat(secondTimestamp.compareTo(thirdTimestamp), is(0));
+    }
+
+    @Test
+    public void givenZonedDateTimes_whenComparing_thenAssertsPass() {
+        ZonedDateTime timeInNewYork = ZonedDateTime.of(2019, 8, 10, 8, 0, 0, 0,
+          ZoneId.of("America/New_York"));
+        ZonedDateTime timeInBerlin = ZonedDateTime.of(2019, 8, 10, 14, 0, 0, 0,
+          ZoneId.of("Europe/Berlin"));
+
+        assertThat(timeInNewYork.isAfter(timeInBerlin), is(false));
+        assertThat(timeInNewYork.isBefore(timeInBerlin), is(false));
+
+        assertThat(timeInNewYork.isEqual(timeInBerlin), is(true));
+        assertThat(timeInNewYork.equals(timeInBerlin), is(false));
+
+        assertThat(timeInNewYork.compareTo(timeInBerlin), is(-1));
+    }
+
+    @Test
+    public void givenLocalTimes_whenComparing_thenAssertsPass() {
+        LocalTime firstTime = LocalTime.of(8, 30);
+        LocalTime secondTime = LocalTime.of(9, 45);
+
+        assertThat(firstTime.isAfter(secondTime), is(false));
+        assertThat(firstTime.isBefore(secondTime), is(true));
+
+        assertThat(firstTime.equals(secondTime), is(false));
+
+        assertThat(firstTime.compareTo(secondTime), is(-1));
+    }
+}

java-dates-2/src/test/java/com/baeldung/date/comparison/LegacyDateComparisonUtilsUnitTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.date.comparison;
+
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.util.Date;
+
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThat;
+
+class LegacyDateComparisonUtilsUnitTest {
+
+    private Date toDate(LocalDateTime localDateTime) {
+        return Date.from(localDateTime.atZone(ZoneId.systemDefault()).toInstant());
+    }
+
+    @Test
+    void givenDatesWithDifferentHours_whenIsSameDay_thenReturnsTrue() {
+        Date firstDate = toDate(LocalDateTime.of(2019, 8, 10, 11, 00, 00));
+        Date secondDate = toDate(LocalDateTime.of(2019, 8, 10, 12, 00, 00));
+        Date thirdDate = toDate(LocalDateTime.of(2019, 8, 15, 12, 00, 00));
+
+        assertThat(LegacyDateComparisonUtils.isSameDay(firstDate, secondDate), is(true));
+        assertThat(LegacyDateComparisonUtils.isSameDay(secondDate, thirdDate), is(false));
+    }
+
+    @Test
+    void givenDatesWithingSameHour_whenIsSameHour_thenReturnsTrue() {
+        Date firstDate = toDate(LocalDateTime.of(2019, 8, 10, 11, 00, 00));
+        Date secondDate = toDate(LocalDateTime.of(2019, 8, 10, 11, 15, 00));
+        Date thirdDate = toDate(LocalDateTime.of(2019, 8, 10, 12, 00, 00));
+
+        assertThat(LegacyDateComparisonUtils.isSameHour(firstDate, secondDate), is(true));
+        assertThat(LegacyDateComparisonUtils.isSameHour(secondDate, thirdDate), is(false));
+    }
+
+    @Test
+    void givenDates__whenComparing_thenAssertsPass() {
+        Date firstDate = toDate(LocalDateTime.of(2019, 8, 10, 0, 00, 00));
+        Date secondDate = toDate(LocalDateTime.of(2019, 8, 15, 0, 00, 00));
+        Date thirdDate = toDate(LocalDateTime.of(2019, 8, 15, 0, 00, 00)); // same date as secondDate
+
+        assertThat(firstDate.after(secondDate), is(false));
+        assertThat(firstDate.before(secondDate), is(true));
+        assertThat(firstDate.compareTo(secondDate), is(-1));
+        assertThat(firstDate.equals(secondDate), is(false));
+
+        assertThat(thirdDate.after(secondDate), is(false));
+        assertThat(thirdDate.before(secondDate), is(false));
+        assertThat(thirdDate.compareTo(secondDate), is(0));
+        assertThat(thirdDate.equals(secondDate), is(true));
+    }
+}