Dates & Times

How dates and times are parsed/formatted in Stroom.

Standard Format

Stroom’s standard format for displaying dates and times is ISO 8601 and specifically in the format

yyyy-MM-dd'T'HH:mm:ss.SSSXX

(where 'T' is the constant T and XX is the timezone offset or Z for Zulu/UTC).

The time part is always represented with three digits for the millisecond part.

Parsing

Parsing is the action of reading a string like 2010-01-01T23:59:59.123Z and converting it into a date/time value.

There are two types of parsing, standard parsing and parsing with an explicit format.

Standard Parsing

The standard format is used when parsing dates with no specific date format, for example in the EffectiveTime header that is used when sending reference data to Stroom.

There is a degree of leniency when parsing date time strings with no explicit format. The following table shows the acceptable date time strings and how they are represented in the standard form.

Input String Standard Form
2010-01-01T23:59:59.1Z 2010-01-01T23:59:59.100Z
2010-01-01T23:59:59.123Z 2010-01-01T23:59:59.123Z
2010-01-01T23:59:59.123456Z 2010-01-01T23:59:59.123Z
2010-01-01T23:59:59.000123Z 2010-01-01T23:59:59.000Z
2010-01-01T23:59:59.0Z 2010-01-01T23:59:59.000Z
2010-01-01T23:59:59.000Z 2010-01-01T23:59:59.000Z
2010-01-01T23:59Z 2010-01-01T23:59:00.000Z
2010-01-01T23:59:59Z 2010-01-01T23:59:59.000Z
2010-01-01T23:59:59+02:00 2010-01-01T23:59:59.000+0200
2010-01-01T23:59:59.123+02 2010-01-01T23:59:59.123+0200
2010-01-01T23:59:59.123+00:00 2010-01-01T23:59:59.123Z
2010-01-01T23:59:59.123+02:00 2010-01-01T23:59:59.123+0200
2010-01-01T23:59:59.123-03:00 2010-01-01T23:59:59.123-0300

Custom Date Formats

Parsing and formatting with an explicit date time format is done in a few places in Stroom.

  • The XSLT function format-date(). This function is a bit of a misnomer as it is doing both parsing and formatting.

  • The Dashboard/Query expression parseDate().

Stroom uses Java’s DateTimeFormatter syntax for expressing an explicit date format.

All letters A to Z and a to z are reserved as pattern letters. The following pattern letters are defined:

Symbol Meaning Presentation Examples
G era text AD, Anno Domini, A
u year year 2004, 04
y year-of-era year 2004, 04
D day-of-year number 189
M/L month-of-year number/text 7, 07, Jul, July, J
d day-of-month number 10
g modified-julian-day number 2451334
Q/q quarter-of-year number/text 3, 03, Q3, 3rd quarter
Y week-based-year year 1996, 96
w week-of-week-based-year number 27
W week-of-month number 4
E day-of-week text Tue, Tuesday, T
e/c localized day-of-week number/text 2, 02, Tue, Tuesday, T
F aligned-week-of-month number 3
a am-pm-of-day text PM
B period-of-day text in the morning
h clock-hour-of-am-pm (1-12) number 12
K hour-of-am-pm (0-11) number 0
k clock-hour-of-day (1-24) number 24
H hour-of-day (0-23) number 0
m minute-of-hour number 30
s second-of-minute number 55
S fraction-of-second fraction 978
A milli-of-day number 1234
n nano-of-second number 987654321
N nano-of-day number 1234000000
V time-zone ID zone-id America/Los_Angeles, Z, -08:30
v generic time-zone name zone-name Pacific Time, PT
z time-zone name zone-name Pacific Standard Time, PST
O localized zone-offset offset-O GMT+8, GMT+08:00, UTC-08:00
X zone-offset Z for zero offset-X Z, -08, -0830, -08:30, -083015, -08:30:15
x zone-offset offset-x +0000, -08, -0830, -08:30, -083015, -08:30:15
Z zone-offset offset-Z +0000, -0800, -08:00
p pad next pad modifier 1
' escape for text delimiter
'' single quote literal '
[ optional section start
] optional section end
# reserved for future use
{ reserved for future use
} reserved for future use

The count of pattern letters determines the format.

Presentation Types

  • Text: The text style is determined based on the number of pattern letters used. Less than 4 pattern letters will use the short form Exactly 4 pattern letters will use the full form Exactly 5 pattern letters will use the narrow form Pattern letters L, c, and q specify the stand-alone form of the text styles.

  • Number: If the count of letters is one, then the value is output using the minimum number of digits and without padding Otherwise, the count of digits is used as the width of the output field, with the value zero-padded as necessary The following pattern letters have constraints on the count of letters Only one letter of c and F can be specified Up to two letters of d, H, h, K, k, m, and s can be specified Up to three letters of D can be specified.

  • Number/Text: If the count of pattern letters is 3 or greater, use the Text rules above Otherwise use the Number rules above.

  • Fraction: Outputs the nano-of-second field as a fraction-of-second The nano-of-second value has nine digits, thus the count of pattern letters is from 1 to 9 If it is less than 9, then the nano-of-second value is truncated, with only the most significant digits being output.

  • Year: The count of letters determines the minimum field width below which padding is used If the count of letters is two, then a reduced two digit form is used For printing, this outputs the rightmost two digits For parsing, this will parse using the base value of 2000, resulting in a year within the range 2000 to 2099 inclusive If the count of letters is less than four (but not two), then the sign is only output for negative years as per SignStyle.NORMAL Otherwise, the sign is output if the pad width is exceeded, as per SignStyle.EXCEEDS_PAD.

  • ZoneId: This outputs the time-zone ID, such as Europe/Paris If the count of letters is two, then the time-zone ID is output Any other count of letters throws IllegalArgumentException.

  • Zone names: This outputs the display name of the time-zone ID If the pattern letter is z the output is the daylight saving aware zone name If there is insufficient information to determine whether DST applies, the name ignoring daylight saving time will be used If the count of letters is one, two or three, then the short name is output If the count of letters is four, then the full name is output Five or more letters throws IllegalArgumentException.

    If the pattern letter is v the output provides the zone name ignoring daylight saving time If the count of letters is one, then the short name is output If the count of letters is four, then the full name is output Two, three and five or more letters throw IllegalArgumentException.

  • Offset X and x: This formats the offset based on the number of pattern letters One letter outputs just the hour, such as +01, unless the minute is non-zero in which case the minute is also output, such as +0130 Two letters outputs the hour and minute, without a colon, such as +0130 Three letters outputs the hour and minute, with a colon, such as +01:30 Four letters outputs the hour and minute and optional second, without a colon, such as +013015 Five letters outputs the hour and minute and optional second, with a colon, such as +01:30:15 Six or more letters throws IllegalArgumentException Pattern letter X (upper case) will output Z when the offset to be output would be zero, whereas pattern letter x (lower case) will output +00, +0000, or +00:00.

  • Offset O: With a non-zero offset, this formats the localized offset based on the number of pattern letters One letter outputs the short form of the localized offset, which is localized offset text, such as GMT, with hour without leading zero, optional 2-digit minute and second if non-zero, and colon, for example GMT+8 Four letters outputs the full form, which is localized offset text, such as GMT, with 2-digit hour and minute field, optional second field if non-zero, and colon, for example GMT+08:00 If the offset is zero, only localized text is output Any other count of letters throws IllegalArgumentException.

  • Offset Z: This formats the offset based on the number of pattern letters One, two or three letters outputs the hour and minute, without a colon, such as +0130 The output will be +0000 when the offset is zero Four letters outputs the full form of localized offset, equivalent to four letters of Offset-O The output will be the corresponding localized offset text if the offset is zero Five letters outputs the hour, minute, with optional second if non-zero, with colon It outputs Z if the offset is zero Six or more letters throws IllegalArgumentException.

  • Optional section: The optional section markers work exactly like calling DateTimeFormatterBuilder.optionalStart() and DateTimeFormatterBuilder.optionalEnd().

  • Pad modifier: Modifies the pattern that immediately follows to be padded with spaces The pad width is determined by the number of pattern letters This is the same as calling DateTimeFormatterBuilder.padNext(int).

For example, ppH outputs the hour-of-day padded on the left with spaces to a width of 2.

Any unrecognized letter is an error Any non-letter character, other than [, ], {, }, # and the single quote will be output directly Despite this, it is recommended to use single quotes around all characters that you want to output directly to ensure that future changes do not break your application.

For further details, see the DateTimeFormatter documentation.

For examples of the parsing/formatting patterns in use, see format-date().

Formatting

Stroom can format dates with an explicit format in a few places:

  • The XSLT function format-date(). This function is a bit of a misnomer as it is both parsing and formatting.

  • The Dashboard/Query expression formatDate().

  • The User Preferences dialog.

When formatting a date time, the format syntax is the same as used in parsing, as shown above.

Durations

Durations are represented in Stroom in two different forms, Stroom Durations and ISO 8601 Durations.

Stroom Duration

Stroom’s standard duration syntax takes the form of a numeric value followed by an optional unit suffix, e.g. 10m for ten minutes.

Prefix Time Unit
milliseconds
ms milliseconds
s seconds
m minutes
h hours
d days

Stroom Duration strings are used in a number of places in Stroom:

ISO 8601 Duration

ISO 8601 durations are an international standard format for expressing durations.

ISO 8601 duration strings are used in a number of places in Stroom:

Date Expressions

Date expressions are a way to represent relative dates or to express simple date arithmetic. They can be used in the following places in Strom:

  • Dashboard expression term values.
  • Dashboard/Query time range settings.
  • Dashboard/Query expression language.

Date expressions consist of a mixture of:

The available relative date functions are:

Function Meaning Example
now() The current time 2024-04-26T17:41:55.239Z
second() The current time rounded down to the last second 2024-04-26T17:41:55.000Z
minute() The current time rounded down to the last minute 2024-04-26T17:41:00.000Z
hour() The current time rounded down to the last hour 2024-04-26T17:00:00.000Z
day() The current time rounded down to the start of the day 2024-04-26T00:00:00.000Z
week() The current time rounded down to the start of the last Monday 2024-04-22T00:00:00.000Z (Monday)
month() The current time rounded down to the start of the month 2024-04-01T00:00:00.000Z
year() The current time rounded down to the start of the year 2024-01-01T00:00:00.000Z

In the examples above, the current time is taken to be 2024-04-26T17:41:55.239Z which is a Friday.

The following are some examples of date expressions:

Expression Result Meaning
now()+1d 2024-04-27T17:41:55.239Z The same time tomorrow.
day() - 1d 2024-04-25T00:00:00.000Z The start of yesterday.
day() +1d +12h 2024-04-27T12:00:00.000Z Noon tomorrow.
2024-04-27T17:41:55.239Z - 24y 2000-04-27T17:41:55.239Z 24 years before 2024-04-27T17:41:55.239Z

In the examples above, the current time is taken to be 2024-04-26T17:41:55.239Z which is a Friday.

Last modified November 13, 2024: Merge branch '7.4' into 7.5 (03eacad)