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 , just get the and index this as a numeric value with Int64Field and use NumericRangeQuery<T> to query it.

Inheritance

System.Object

DateTools

Namespace: Lucene.Net.Documents

Assembly: Lucene.Net.dll

Syntax

public static class DateTools : object

Methods

DateToString(DateTime, DateTools.Resolution)

Converts a to a string suitable for indexing.

Declaration

public static string DateToString(DateTime date, DateTools.Resolution resolution)

Parameters

Type	Name	Description
DateTime	date	the date to be converted
DateTools.Resolution	resolution	the desired resolution, see Round(DateTime, DateTools.Resolution)

Returns

Type	Description
System.String	a string in format yyyyMMddHHmmssSSS or shorter, depending on resolution; using GMT as timezone

Round(DateTime, DateTools.Resolution)

Limit a date's resolution. For example, the date 2004-09-21 13:50:11 will be changed to 2004-09-01 00:00:00 when using MONTH.

Declaration

public static DateTime Round(DateTime date, DateTools.Resolution resolution)

Parameters

Type	Name	Description
DateTime	date	the date to be rounded
DateTools.Resolution	resolution	The desired resolution of the date to be returned

Returns

Type	Description
DateTime	the date with all values more precise than resolution set to 0 or 1

Round(Int64, DateTools.Resolution)

Limit a date's resolution. For example, the date 1095767411000 (which represents 2004-09-21 13:50:11) will be changed to 1093989600000 (2004-09-01 00:00:00) when using MONTH.

Declaration

public static long Round(long time, DateTools.Resolution resolution)

Parameters

Type	Name	Description
System.Int64	time	the time to be rounded
DateTools.Resolution	resolution	The desired resolution of the date to be returned

Returns

Type	Description
System.Int64	the date with all values more precise than resolution set to 0 or 1, expressed as milliseconds since January 1, 1970, 00:00:00 GMT (also known as the "epoch")

StringToDate(String)

Converts a string produced by TimeToString(Int64, DateTools.Resolution) or DateToString(DateTime, DateTools.Resolution) back to a time, represented as a object.

Declaration

public static DateTime StringToDate(string dateString)

Parameters

Type	Name	Description
System.String	dateString	the date string to be converted

Returns

Type	Description
DateTime	the parsed time as a object

StringToTime(String)

Converts a string produced by TimeToString(Int64, DateTools.Resolution) or DateToString(DateTime, DateTools.Resolution) back to a time, represented as the number of milliseconds since January 1, 1970, 00:00:00 GMT (also known as the "epoch").

Declaration

public static long StringToTime(string dateString)

Parameters

Type	Name	Description
System.String	dateString	the date string to be converted

Returns

Type	Description
System.Int64	the number of milliseconds since January 1, 1970, 00:00:00 GMT (also known as the "epoch")

TimeToString(Int64, DateTools.Resolution)

Converts a millisecond time to a string suitable for indexing.

Declaration

public static string TimeToString(long time, DateTools.Resolution resolution)

Parameters

Type	Name	Description
System.Int64	time	the date expressed as milliseconds since January 1, 1970, 00:00:00 GMT (also known as the "epoch")
DateTools.Resolution	resolution	the desired resolution, see Round(Int64, DateTools.Resolution)

Returns

Type	Description
System.String	a string in format yyyyMMddHHmmssSSS or shorter, depending on resolution; using GMT as timezone