TM-138: DateUtil doesn't support sub-hour offset timezones.

common/common-lang/src/main/java/com/twelvemonkeys/lang/DateUtil.java

@@ -142,7 +142,7 @@ public final class DateUtil {
      * @param pTime time
      * @return the time rounded to the closest second.
      */
-    public static long roundToSecond(long pTime) {
+    public static long roundToSecond(final long pTime) {
         return (pTime / SECOND) * SECOND;
     }
 
@@ -152,7 +152,7 @@ public final class DateUtil {
      * @param pTime time
      * @return the time rounded to the closest minute.
      */
-    public static long roundToMinute(long pTime) {
+    public static long roundToMinute(final long pTime) {
         return (pTime / MINUTE) * MINUTE;
     }
 
@@ -162,9 +162,20 @@ public final class DateUtil {
      * @param pTime time
      * @return the time rounded to the closest hour.
      */
-    public static long roundToHour(long pTime) {
+    public static long roundToHour(final long pTime) {
-        // TODO: What if timezone offset is sub hour? Are there any? I think so...
+        return roundToHour(pTime, TimeZone.getDefault());
-        return ((pTime / HOUR) * HOUR);
+    }
+
+    /**
+     * Rounds the given time down to the closest hour, using the given timezone.
+     *
+     * @param pTime time
+     * @param pTimeZone the timezone to use when rounding
+     * @return the time rounded to the closest hour.
+     */
+    public static long roundToHour(final long pTime, final TimeZone pTimeZone) {
+        int offset = pTimeZone.getOffset(pTime);
+        return ((pTime / HOUR) * HOUR) - offset;
     }
 
     /**
@@ -173,7 +184,7 @@ public final class DateUtil {
      * @param pTime time
      * @return the time rounded to the closest day.
      */
-    public static long roundToDay(long pTime) {
+    public static long roundToDay(final long pTime) {
         return roundToDay(pTime, TimeZone.getDefault());
     }
 
@@ -184,7 +195,7 @@ public final class DateUtil {
      * @param pTimeZone the timezone to use when rounding
      * @return the time rounded to the closest day.
      */
-    public static long roundToDay(long pTime, TimeZone pTimeZone) {
+    public static long roundToDay(final long pTime, final TimeZone pTimeZone) {
         int offset = pTimeZone.getOffset(pTime);
         return (((pTime  + offset) / DAY) * DAY) - offset;
     }

common/common-lang/src/test/java/com/twelvemonkeys/lang/DateUtilTest.java

@@ -29,11 +29,15 @@
 package com.twelvemonkeys.lang;
 
 import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
 
+import java.util.Arrays;
 import java.util.Calendar;
+import java.util.List;
 import java.util.TimeZone;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
 
 /**
  * DateUtilTest
@@ -42,9 +46,30 @@ import static org.junit.Assert.*;
  * @author last modified by $Author: haraldk$
  * @version $Id: DateUtilTest.java,v 1.0 11.04.12 16:21 haraldk Exp$
  */
+@RunWith(Parameterized.class)
 public class DateUtilTest {
-    private static Calendar getCalendar(long time) {
+
-        Calendar calendar = Calendar.getInstance(TimeZone.getDefault());
+    private final TimeZone timeZone;
+
+    @Parameterized.Parameters
+    public static List<Object[]> timeZones() {
+        return Arrays.asList(new Object[][] {
+                {TimeZone.getTimeZone("UTC")},
+                {TimeZone.getTimeZone("CET")},
+                {TimeZone.getTimeZone("IST")}, // 30 min off
+        });
+    }
+
+    public DateUtilTest(final TimeZone timeZone) {
+        this.timeZone = timeZone;
+    }
+
+    private Calendar getCalendar(long time) {
+        return getCalendar(time, TimeZone.getDefault());
+    }
+
+    private Calendar getCalendar(long time, final TimeZone timeZone) {
+        Calendar calendar = Calendar.getInstance(timeZone);
         calendar.setTimeInMillis(time);
 
         return calendar;
@@ -74,6 +99,15 @@ public class DateUtilTest {
         assertEquals(0, calendar.get(Calendar.MINUTE));
     }
 
+    @Test
+    public void testRoundToHourTZ() {
+        Calendar calendar = getCalendar(DateUtil.roundToHour(System.currentTimeMillis(), timeZone), timeZone);
+
+        assertEquals(0, calendar.get(Calendar.MILLISECOND));
+        assertEquals(0, calendar.get(Calendar.SECOND));
+        assertEquals(0, calendar.get(Calendar.MINUTE));
+    }
+
     @Test
     public void testRoundToDay() {
         Calendar calendar = getCalendar(DateUtil.roundToDay(System.currentTimeMillis()));
@@ -84,6 +118,16 @@ public class DateUtilTest {
         assertEquals(0, calendar.get(Calendar.HOUR_OF_DAY));
     }
 
+    @Test
+    public void testRoundToDayTZ() {
+        Calendar calendar = getCalendar(DateUtil.roundToDay(System.currentTimeMillis(), timeZone), timeZone);
+
+        assertEquals(0, calendar.get(Calendar.MILLISECOND));
+        assertEquals(0, calendar.get(Calendar.SECOND));
+        assertEquals(0, calendar.get(Calendar.MINUTE));
+        assertEquals(0, calendar.get(Calendar.HOUR_OF_DAY));
+    }
+
     @Test
     public void testCurrentTimeSecond() {
         Calendar calendar = getCalendar(DateUtil.currentTimeSecond());
@@ -106,6 +150,7 @@ public class DateUtilTest {
         assertEquals(0, calendar.get(Calendar.MILLISECOND));
         assertEquals(0, calendar.get(Calendar.SECOND));
         assertEquals(0, calendar.get(Calendar.MINUTE));
+//        assertEquals((TimeZone.getDefault().getOffset(calendar.getTimeInMillis()) / DateUtil.MINUTE) % 60, calendar.get(Calendar.MINUTE));
     }
 
     @Test
@@ -114,6 +159,7 @@ public class DateUtilTest {
 
         assertEquals(0, calendar.get(Calendar.MILLISECOND));
         assertEquals(0, calendar.get(Calendar.SECOND));
+//        assertEquals((TimeZone.getDefault().getOffset(calendar.getTimeInMillis()) / DateUtil.MINUTE) % 60, calendar.get(Calendar.MINUTE));
         assertEquals(0, calendar.get(Calendar.MINUTE));
         assertEquals(0, calendar.get(Calendar.HOUR_OF_DAY));
     }