org.apache.lucene.document

Class DateField

public class DateField extends Object

Provides support for converting dates to strings and vice-versa. The strings are structured so that lexicographic sorting orders by date, which makes them suitable for use as field values and search terms.

Note that you do not have to use this class, you can just save your dates as strings if lexicographic sorting orders them by date. This is the case for example for dates like yyyy-mm-dd hh:mm:ss (of course you can leave out the delimiter characters to save some space). The advantage with using such a format is that you can easily save dates with the required granularity, e.g. leaving out seconds. This saves memory when searching with a RangeQuery or PrefixQuery, as Lucene expands these queries to a BooleanQuery with potentially very many terms.

Note: dates before 1970 cannot be used, and therefore cannot be indexed when using this class.

Method Summary
static StringdateToString(Date date)
Converts a Date to a string suitable for indexing.
static StringMAX_DATE_STRING()
static StringMIN_DATE_STRING()
static DatestringToDate(String s)
Converts a string-encoded date into a Date object.
static longstringToTime(String s)
Converts a string-encoded date into a millisecond time.
static StringtimeToString(long time)
Converts a millisecond time to a string suitable for indexing.

Method Detail

dateToString

public static String dateToString(Date date)
Converts a Date to a string suitable for indexing.

Throws: RuntimeException if the date specified in the method argument is before 1970

MAX_DATE_STRING

public static String MAX_DATE_STRING()

MIN_DATE_STRING

public static String MIN_DATE_STRING()

stringToDate

public static Date stringToDate(String s)
Converts a string-encoded date into a Date object.

stringToTime

public static long stringToTime(String s)
Converts a string-encoded date into a millisecond time.

timeToString

public static String timeToString(long time)
Converts a millisecond time to a string suitable for indexing.

Throws: RuntimeException if the time specified in the method argument is negative, that is, before 1970

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