net.snowflake.common.util

Class TimeUtil

java.lang.Object

net.snowflake.common.util.TimeUtil

public class TimeUtil
extends Object

Time-related utilities

Author:

mzukowski

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	TimeUtil.CCompatibleTimeZone Custom TimeZone implementations can be compatible with C libraries regarding ambiguous and illegal timestamps.
static class	TimeUtil.TimestampType
static class	TimeUtil.TimestampUnit

Constructor Summary

Constructors

Constructor and Description
TimeUtil()

Method Summary

Modifier and Type	Method and Description
static SFTime	getSFTime(String obj, int scale) Convert a time internal value (scaled number of seconds + fractional seconds) into an SFTime.
static SFTimestamp	getSFTimestamp(String timestampStr, int scale, TimeUtil.TimestampType internalColumnType, long resultVersion, TimeZone sessionTZ) Convert a timestamp internal value (scaled number of seconds + fractional seconds) into a SFTimestamp.
static SFTimestamp	getSFTimestamp(String timestampStr, TimeUtil.TimestampUnit unit, int scale, TimeUtil.TimestampType internalColumnType, long resultVersion, TimeZone sessionTZ) Convert a timestamp internal value (scaled number of seconds + fractional seconds or nanoseconds) into a SFTimestamp.
static int	getYearAsInt(Calendar cal) Extracts YEAR as a signed integer, taking care of BC.
static boolean	isDSTAmbiguous(long dateInMs, TimeZone tz) Returns true if the specified instant corresponds to a wallclock time that is "ambiguous" in the given timezone because of daylight saving time rules.
static boolean	isDSTIllegal(int era, int year, int month, int dayOfMonth, int dayOfWeek, int millisecondWithinDay, TimeZone tz) Returns true if the specified instant is illegal in the current timezone because of daylight saving time rules.
static Timestamp	timestampFromNs(BigDecimal ns) Converts the number of nanoseconds into a java.sql.Timestamp, if that is possible.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TimeUtil

public TimeUtil()

Method Detail

timestampFromNs

public static Timestamp timestampFromNs(BigDecimal ns)

Converts the number of nanoseconds into a java.sql.Timestamp, if that is possible. (java.sql.Timestamp can only accommodate timestamps where the number of millis since epoch can be represented by a long). Note: this method will adjust timestamp before 1582-10-05 to be Gregorian Calendar (by default java use Julian Calendar)

Parameters:

ns - a BigDecimal value

Returns:

timestamp, or null if ns is outside the range of Java timestamps

getSFTimestamp

public static SFTimestamp getSFTimestamp(String timestampStr,
                                         int scale,
                                         TimeUtil.TimestampType internalColumnType,
                                         long resultVersion,
                                         TimeZone sessionTZ)
                                  throws IllegalArgumentException

Convert a timestamp internal value (scaled number of seconds + fractional seconds) into a SFTimestamp.

Parameters:

timestampStr - timestamp object

scale - timestamp scale

internalColumnType - snowflake timestamp type

resultVersion - For new result version, timestamp with timezone is formatted as the seconds since epoch with fractional part in the decimal followed by time zone index. E.g.: "123.456 1440". Here 123.456 is the * number of seconds since epoch and 1440 is the timezone index.

sessionTZ - session timezone

Returns:

converted snowflake timestamp object

Throws:

IllegalArgumentException - if timestampStr is an invalid timestamp

getSFTimestamp

public static SFTimestamp getSFTimestamp(String timestampStr,
                                         TimeUtil.TimestampUnit unit,
                                         int scale,
                                         TimeUtil.TimestampType internalColumnType,
                                         long resultVersion,
                                         TimeZone sessionTZ)
                                  throws IllegalArgumentException

Convert a timestamp internal value (scaled number of seconds + fractional seconds or nanoseconds) into a SFTimestamp.

Parameters:

timestampStr - timestamp object

unit - IN_SECONDS or IN_NANOSECONDS, a unit of epoch time in timestampStr

scale - timestamp scale for IN_SECONDS. Must be 0 for IN_NANOSECONDS.

internalColumnType - snowflake timestamp type

resultVersion - For new result version, timestamp with timezone is formatted as the seconds since epoch with fractional part in the decimal followed by time zone index. E.g.: "123.456 1440". Here 123.456 is the * number of seconds since epoch and 1440 is the timezone index.

sessionTZ - session timezone

Returns:

converted snowflake timestamp object

Throws:

IllegalArgumentException - if timestampStr is an invalid timestamp

getSFTime

public static SFTime getSFTime(String obj,
                               int scale)
                        throws IllegalArgumentException

Convert a time internal value (scaled number of seconds + fractional seconds) into an SFTime. Example: getSFTime("123.456", 5) returns an SFTime for 00:02:03.45600.

Parameters:

obj - time object

scale - time scale

Returns:

snowflake time object

Throws:

IllegalArgumentException - if time is invalid

isDSTAmbiguous

public static boolean isDSTAmbiguous(long dateInMs,
                                     TimeZone tz)

Returns true if the specified instant corresponds to a wallclock time that is "ambiguous" in the given timezone because of daylight saving time rules. For example, '2016-11-06 01:30' is ambiguous in time zone 'America/Los_Angeles', because the clock goes from 2:00 back to 1:00; so '2016-11-06 01:30 PT' can mean either '2016-11-06 08:30 GMT' or '2016-01-30 09:30 GMT'. Always returns false for instances of CCompatibleTimeZone.

Parameters:

dateInMs -

tz -

Returns:

true if the given timestamp is ambiguous due to DST rules.

isDSTIllegal

public static boolean isDSTIllegal(int era,
                                   int year,
                                   int month,
                                   int dayOfMonth,
                                   int dayOfWeek,
                                   int millisecondWithinDay,
                                   TimeZone tz)

Returns true if the specified instant is illegal in the current timezone because of daylight saving time rules. For example, '2016-03-13 02:30' is illegal in time zone 'America/Los_Angeles', because the clock goes from 2:00 straight to 3:00. (Note that illegal timestamps can't be detected from millis since epoch, since an illegal timestamp will be mapped to a legal timestamp as it is converted to millis since epoch. We need the timestamp to be broken into its components. Hence the asymmetry in the arguments compared to isDSTAmbiguous()). Always returns false for instances of CCompatibleTimeZone.

Parameters:

era -

year -

month -

dayOfMonth -

dayOfWeek -

millisecondWithinDay -

tz -

Returns:

true if the given timestamp is illegal due to DST rules.

getYearAsInt

public static int getYearAsInt(Calendar cal)

Extracts YEAR as a signed integer, taking care of BC.

Parameters:

cal - calendar to extract YEAR from

Returns:

ISO year extracted