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java.lang.Objectorg.apache.lucene.document.DateTools
public class DateTools
Provides support for converting dates to strings and vice-versa. The strings are structured so that lexicographic sorting orders them by date, which makes them suitable for use as field values and search terms.
This class also helps you to limit the resolution of your dates. Do not
save dates with a finer resolution than you really need, as then
TermRangeQuery
and PrefixQuery
will require more memory and become slower.
Another approach is NumericUtils
, which provides
a sortable binary representation (prefix encoded) of numeric values, which
date/time are.
For indexing a Date
or Calendar
, just get the unix timestamp as
long
using Date.getTime()
or Calendar.getTimeInMillis()
and
index this as a numeric value with LongField
and use NumericRangeQuery
to query it.
Nested Class Summary | |
---|---|
static class |
DateTools.Resolution
Specifies the time granularity. |
Method Summary | |
---|---|
static String |
dateToString(Date date,
DateTools.Resolution resolution)
Converts a Date to a string suitable for indexing. |
static Date |
round(Date date,
DateTools.Resolution resolution)
Limit a date's resolution. |
static long |
round(long time,
DateTools.Resolution resolution)
Limit a date's resolution. |
static Date |
stringToDate(String dateString)
Converts a string produced by timeToString or
dateToString back to a time, represented as a
Date object. |
static long |
stringToTime(String dateString)
Converts a string produced by timeToString or
dateToString back to a time, represented as the
number of milliseconds since January 1, 1970, 00:00:00 GMT. |
static String |
timeToString(long time,
DateTools.Resolution resolution)
Converts a millisecond time to a string suitable for indexing. |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Method Detail |
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public static String dateToString(Date date, DateTools.Resolution resolution)
date
- the date to be convertedresolution
- the desired resolution, see
round(Date, DateTools.Resolution)
yyyyMMddHHmmssSSS
or shorter,
depending on resolution
; using GMT as timezonepublic static String timeToString(long time, DateTools.Resolution resolution)
time
- the date expressed as milliseconds since January 1, 1970, 00:00:00 GMTresolution
- the desired resolution, see
round(long, DateTools.Resolution)
yyyyMMddHHmmssSSS
or shorter,
depending on resolution
; using GMT as timezonepublic static long stringToTime(String dateString) throws ParseException
timeToString
or
dateToString
back to a time, represented as the
number of milliseconds since January 1, 1970, 00:00:00 GMT.
dateString
- the date string to be converted
ParseException
- if dateString
is not in the
expected formatpublic static Date stringToDate(String dateString) throws ParseException
timeToString
or
dateToString
back to a time, represented as a
Date object.
dateString
- the date string to be converted
ParseException
- if dateString
is not in the
expected formatpublic static Date round(Date date, DateTools.Resolution resolution)
2004-09-21 13:50:11
will be changed to 2004-09-01 00:00:00
when using
Resolution.MONTH
.
resolution
- The desired resolution of the date to be returned
resolution
set to 0 or 1public static long round(long time, DateTools.Resolution resolution)
1095767411000
(which represents 2004-09-21 13:50:11) will be changed to
1093989600000
(2004-09-01 00:00:00) when using
Resolution.MONTH
.
resolution
- The desired resolution of the date to be returned
resolution
set to 0 or 1, expressed as milliseconds since January 1, 1970, 00:00:00 GMT
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