public class DateMathParser extends Object
The basic syntax support addition, subtraction and rounding at various levels of granularity (or "units"). Commands can be chained together and are parsed from left to right. '+' and '-' denote addition and subtraction, while '/' denotes "round". Round requires only a unit, while addition/subtraction require an integer value and a unit. Command strings must not include white space, but the "No-Op" command (empty string) is allowed....
/HOUR ... Round to the start of the current hour /DAY ... Round to the start of the current day +2YEARS ... Exactly two years in the future from now -1DAY ... Exactly 1 day prior to now /DAY+6MONTHS+3DAYS ... 6 months and 3 days in the future from the start of the current day +6MONTHS+3DAYS/DAY ... 6 months and 3 days in the future from now, rounded down to nearest day
(Multiple aliases exist for the various units of time (ie:
MILLISECONDS.) The complete list can be found by
inspecting the keySet of
All commands are relative to a "now" which is fixed in an instance of
DateMathParser such that
no matter how many wall clock milliseconds elapse between the two
distinct calls to parse (Assuming no other thread calls
setNow" in the interim). The default value of 'now' is
the time at the moment the
DateMathParser instance is
constructed, unless overridden by the
All commands are also affected to the rules of a specified
(including the start/end of DST if any) which determine when each arbitrary
day starts. This not only impacts rounding/adding of DAYs, but also
cascades to rounding of HOUR, MIN, MONTH, YEAR as well. The default
TimeZone used is
UTC unless overridden by the
Historical dates: The calendar computation is completely done with the
Gregorian system/algorithm. It does not switch to Julian or
anything else, unlike the default
|Modifier and Type||Field and Description|
A mapping from (uppercased) String labels identifying time units, to the corresponding
Default TimeZone for DateMath rounding (UTC)
|Constructor and Description|
Default constructor that assumes UTC should be used for rounding unless otherwise specified in the SolrRequestInfo
|Modifier and Type||Method and Description|
Returns a clone of this instance's concept of "now" (never null).
Parses a String which may be a date (in the standard ISO-8601 format) followed by an optional math expression.
Parses a string of commands relative "now" are returns the resulting Date.
Defines this instance's concept of "now".
public static final TimeZone UTC
public static final TimeZone DEFAULT_MATH_TZ
public static final DateTimeFormatter PARSER
DateTimeFormatter.ISO_INSTANTin that it's lenient.
public static final Map<String,ChronoUnit> CALENDAR_UNITS
ChronoUnitenum (e.g. "YEARS") used to set/add/roll that unit of measurement.
A single logical unit of time might be represented by multiple labels
for convenience (ie:
public DateMathParser(TimeZone tz)
tz- The TimeZone used for rounding (to determine when hours/days begin). If null, then this method defaults to the value dictated by the SolrRequestInfo if it exists -- otherwise it uses UTC.
public static Date parseMath(Date now, String val)
now- an optional fixed date to use as "NOW"
val- the string to parse
public TimeZone getTimeZone()
public Date getNow()
public Date parseMath(String math) throws ParseException
ParseException- positions in ParseExceptions are token positions, not character positions.
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