DateTools needs to use UTC for correct collation (LUCENE-491), patch by John Haxby

git-svn-id: https://svn.apache.org/repos/asf/lucene/java/trunk@375070 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/lucene/document/DateTools.java

@@ -20,6 +20,7 @@ import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.Date;
+import java.util.TimeZone;
 
 /**
  * Provides support for converting dates to strings and vice-versa.
@@ -36,6 +37,8 @@ import java.util.Date;
  * is set to <code>Resolution.DAY</code> or lower.
  */
 public class DateTools {
+  
+  private final static TimeZone GMT = TimeZone.getTimeZone("GMT");
 
   private DateTools() {}
 
@@ -46,7 +49,7 @@ public class DateTools {
    * @param resolution the desired resolution, see
    *  {@link #round(Date, DateTools.Resolution)}
    * @return a string in format <code>yyyyMMddHHmmssSSS</code> or shorter,
-   *  depeding on <code>resolution</code>
+   *  depeding on <code>resolution</code>; using UTC as timezone 
    */
   public static String dateToString(Date date, Resolution resolution) {
     return timeToString(date.getTime(), resolution);
@@ -59,10 +62,10 @@ public class DateTools {
    * @param resolution the desired resolution, see
    *  {@link #round(long, DateTools.Resolution)}
    * @return a string in format <code>yyyyMMddHHmmssSSS</code> or shorter,
-   *  depeding on <code>resolution</code>
+   *  depeding on <code>resolution</code>; using UTC as timezone
    */
   public static String timeToString(long time, Resolution resolution) {
-    Calendar cal = Calendar.getInstance();
+    Calendar cal = Calendar.getInstance(GMT);
 
     //protected in JDK's prior to 1.4
     //cal.setTimeInMillis(round(time, resolution));
@@ -70,6 +73,7 @@ public class DateTools {
     cal.setTime(new Date(round(time, resolution)));
 
     SimpleDateFormat sdf = new SimpleDateFormat();
+    sdf.setTimeZone(GMT);
     String pattern = null;
     if (resolution == Resolution.YEAR) {
       pattern = "yyyy";
@@ -135,6 +139,7 @@ public class DateTools {
     else
       throw new ParseException("Input is not valid date string: " + dateString, 0);
     SimpleDateFormat sdf = new SimpleDateFormat(pattern);
+    sdf.setTimeZone(GMT);
     Date date = sdf.parse(dateString);
     return date;
   }
@@ -163,7 +168,7 @@ public class DateTools {
    *  set to 0 or 1, expressed as milliseconds since January 1, 1970, 00:00:00 GMT
    */
   public static long round(long time, Resolution resolution) {
-    Calendar cal = Calendar.getInstance();
+    Calendar cal = Calendar.getInstance(GMT);
 
     // protected in JDK's prior to 1.4
     //cal.setTimeInMillis(time);

src/test/org/apache/lucene/document/TestDateTools.java

@@ -4,6 +4,7 @@ import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.Date;
+import java.util.TimeZone;
 
 import junit.framework.TestCase;
 
@@ -58,6 +59,7 @@ public class TestDateTools extends TestCase {
     cal.set(1970, 0, 1,    // year=1970, month=january, day=1
         0, 0, 0);          // hour, minute, second
     cal.set(Calendar.MILLISECOND, 0);
+    cal.setTimeZone(TimeZone.getTimeZone("GMT"));
     assertEquals(cal.getTime().getTime(), time);
     cal.set(1980, 1, 2,    // year=1980, month=february, day=2
         11, 5, 0);          // hour, minute, second
@@ -68,6 +70,7 @@ public class TestDateTools extends TestCase {
   
   public void testDateAndTimetoString() throws ParseException {
     Calendar cal = Calendar.getInstance();
+    cal.setTimeZone(TimeZone.getTimeZone("GMT"));
     cal.set(2004, 1, 3,   // year=2004, month=february(!), day=3
         22, 8, 56);       // hour, minute, second
     cal.set(Calendar.MILLISECOND, 333);
@@ -131,6 +134,7 @@ public class TestDateTools extends TestCase {
   
   public void testRound() {
     Calendar cal = Calendar.getInstance();
+    cal.setTimeZone(TimeZone.getTimeZone("GMT"));
     cal.set(2004, 1, 3,   // year=2004, month=february(!), day=3
         22, 8, 56);       // hour, minute, second
     cal.set(Calendar.MILLISECOND, 333);
@@ -168,7 +172,23 @@ public class TestDateTools extends TestCase {
 
   private String isoFormat(Date date) {
     SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS");
+    sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
     return sdf.format(date);
   }
 
+  public void testDateToolsUTC() throws Exception {
+    // Sun, 30 Oct 2005 00:00:00 +0000 -- the last second of 2005's DST in Europe/London
+    long time = 1130630400;
+    try {
+        TimeZone.setDefault(TimeZone.getTimeZone(/* "GMT" */ "Europe/London"));
+        String d1 = DateTools.dateToString(new Date(time*1000), DateTools.Resolution.MINUTE);
+        String d2 = DateTools.dateToString(new Date((time+3600)*1000), DateTools.Resolution.MINUTE);
+        assertFalse("different times", d1.equals(d2));
+        assertEquals("midnight", DateTools.stringToTime(d1), time*1000);
+        assertEquals("later", DateTools.stringToTime(d2), (time+3600)*1000);
+    } finally {
+        TimeZone.setDefault(null);
+    }
+  }
+
 }