net.opentsdb.utils

Class DateTime

java.lang.Object

net.opentsdb.utils.DateTime

public class DateTime
extends Object

Utility class that provides helpers for dealing with dates and timestamps. In particular, this class handles parsing relative or human readable date/time strings provided in queries.

Since:

2.0

Field Summary

Fields

Modifier and Type	Field and Description
static HashMap<String,TimeZone>	timezones Immutable cache mapping a timezone name to its object.

Constructor Summary

Constructors

Constructor and Description
DateTime()

Method Summary

Methods

Modifier and Type	Method and Description
static boolean	isRelativeDate(String value) Returns whether or not a date is specified in a relative fashion.
static long	parseDateTimeString(String datetime, String tz) Attempts to parse a timestamp from a given string Formats accepted are: Relative: 5m-ago, 1h-ago, etc.
static long	parseDuration(String duration) Parses a human-readable duration (e.g, "10m", "3h", "14d") into seconds.
static void	setDefaultTimezone(String tzname) Sets the default timezone for this running OpenTSDB instance
static void	setTimeZone(SimpleDateFormat fmt, String tzname) Applies the given timezone to the given date format.

Methods inherited from class java.lang.Object

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

Field Detail

timezones

public static final HashMap<String,TimeZone> timezones

Immutable cache mapping a timezone name to its object. We do this because the JDK's TimeZone class was implemented by retards, and it's synchronized, going through a huge pile of code, and allocating new objects all the time. And to make things even better, if you ask for a TimeZone that doesn't exist, it returns GMT! It is thus impractical to tell if the timezone name was valid or not. JDK_brain_damage++; Note: caching everything wastes a few KB on RAM (34KB on my system with 611 timezones -- each instance is 56 bytes with the Sun JDK).

Constructor Detail

DateTime

public DateTime()

Method Detail

parseDateTimeString

public static final long parseDateTimeString(String datetime,
                       String tz)

Attempts to parse a timestamp from a given string Formats accepted are:

• Relative: 5m-ago, 1h-ago, etc. See parseDuration(java.lang.String)
• Absolute human readable dates:
  • "yyyy/MM/dd-HH:mm:ss"
  • "yyyy/MM/dd HH:mm:ss"
  • "yyyy/MM/dd-HH:mm"
  • "yyyy/MM/dd HH:mm"
  • "yyyy/MM/dd"
• Unix Timestamp in seconds or milliseconds:
  • 1355961600
  • 1355961600000
  • 1355961600.000

Parameters:

datetime - The string to parse a value for

Returns:

A Unix epoch timestamp in milliseconds

Throws:

NullPointerException - if the timestamp is null

IllegalArgumentException - if the request was malformed

parseDuration

public static final long parseDuration(String duration)

Parses a human-readable duration (e.g, "10m", "3h", "14d") into seconds.

Formats supported:

• ms: milliseconds
• s: seconds
• m: minutes
• h: hours
• d: days
• w: weeks
• n: month (30 days)
• y: years (365 days)

Parameters:

duration - The human-readable duration to parse.

Returns:

A strictly positive number of milliseconds.

Throws:

IllegalArgumentException - if the interval was malformed.

isRelativeDate

public static boolean isRelativeDate(String value)

Returns whether or not a date is specified in a relative fashion.

A date is specified in a relative fashion if it ends in "-ago", e.g. 1d-ago is the same as 24h-ago.

Parameters:

value - The value to parse

Returns:

true if the parameter is passed and is a relative date. Note the method doesn't attempt to validate the relative date. So this function can return true on something that looks like a relative date, but is actually invalid once we really try to parse it.

Throws:

NullPointerException - if the value is null

setTimeZone

public static void setTimeZone(SimpleDateFormat fmt,
               String tzname)

Applies the given timezone to the given date format.

Parameters:

fmt - Date format to apply the timezone to.

tzname - Name of the timezone, or null in which case this function is a no-op.

Throws:

IllegalArgumentException - if tzname isn't a valid timezone name.

NullPointerException - if the format is null

setDefaultTimezone

public static void setDefaultTimezone(String tzname)

Sets the default timezone for this running OpenTSDB instance

WARNING If OpenTSDB is used with a Security Manager, setting the default timezone only works for the running thread. Otherwise it will work for the entire application.

Parameters:

tzname - Name of the timezone to use

Throws:

IllegalArgumentException - if tzname isn't a valid timezone name