Class TimeZone
In: activesupport/lib/active_support/values/time_zone.rb
Parent: Object

A value object representing a time zone. A time zone is simply a named offset (in seconds) from GMT. Note that two time zone objects are only equivalent if they have both the same offset, and the same name.

A TimeZone instance may be used to convert a Time value to the corresponding time zone.

The class also includes all, which returns a list of all TimeZone objects.

Methods

<=>   []   adjust   all   create   formatted_offset   new   new   now   to_s   today   unadjust   us_zones  

Included Modules

Comparable

Constants

US_ZONES = /US|Arizona|Indiana|Hawaii|Alaska/ unless defined?(US_ZONES)   A regular expression that matches the names of all time zones in the USA.

Attributes

name  [R] 
utc_offset  [R] 

Public Class methods

[](arg)

Locate a specific time zone object. If the argument is a string, it is interpreted to mean the name of the timezone to locate. If it is a numeric value it is either the hour offset, or the second offset, of the timezone to find. (The first one with that offset will be returned.) Returns nil if no such time zone is known to the system.

[Source]

# File activesupport/lib/active_support/values/time_zone.rb, line 158
    def [](arg)
      case arg
        when String
          all.find { |z| z.name == arg }
        when Numeric
          arg *= 3600 if arg.abs <= 13
          all.find { |z| z.utc_offset == arg.to_i }
        else
          raise ArgumentError, "invalid argument to TimeZone[]: #{arg.inspect}"
      end
    end
all()

Return an array of all TimeZone objects. There are multiple TimeZone objects per time zone, in many cases, to make it easier for users to find their own time zone.

[Source]

# File activesupport/lib/active_support/values/time_zone.rb, line 93
    def all
      unless @@zones
        @@zones = []
        [[-43_200, "International Date Line West" ],
         [-39_600, "Midway Island", "Samoa" ],
         [-36_000, "Hawaii" ],
         [-32_400, "Alaska" ],
         [-28_800, "Pacific Time (US & Canada)", "Tijuana" ],
         [-25_200, "Mountain Time (US & Canada)", "Chihuahua", "Mazatlan", 
                   "Arizona" ],
         [-21_600, "Central Time (US & Canada)", "Saskatchewan", "Guadalajara",
                   "Mexico City", "Monterrey", "Central America" ],
         [-18_000, "Eastern Time (US & Canada)", "Indiana (East)", "Bogota",
                   "Lima", "Quito" ],
         [-14_400, "Atlantic Time (Canada)", "Caracas", "La Paz", "Santiago" ],
         [-12_600, "Newfoundland" ],
         [-10_800, "Brasilia", "Buenos Aires", "Georgetown", "Greenland" ],
         [ -7_200, "Mid-Atlantic" ],
         [ -3_600, "Azores", "Cape Verde Is." ],
         [      0, "Dublin", "Edinburgh", "Lisbon", "London", "Casablanca",
                   "Monrovia" ],
         [  3_600, "Belgrade", "Bratislava", "Budapest", "Ljubljana", "Prague",
                   "Sarajevo", "Skopje", "Warsaw", "Zagreb", "Brussels",
                   "Copenhagen", "Madrid", "Paris", "Amsterdam", "Berlin",
                   "Bern", "Rome", "Stockholm", "Vienna",
                   "West Central Africa" ],
         [  7_200, "Bucharest", "Cairo", "Helsinki", "Kyev", "Riga", "Sofia",
                   "Tallinn", "Vilnius", "Athens", "Istanbul", "Minsk",
                   "Jerusalem", "Harare", "Pretoria" ],
         [ 10_800, "Moscow", "St. Petersburg", "Volgograd", "Kuwait", "Riyadh",
                   "Nairobi", "Baghdad" ],
         [ 12_600, "Tehran" ],
         [ 14_400, "Abu Dhabi", "Muscat", "Baku", "Tbilisi", "Yerevan" ],
         [ 16_200, "Kabul" ],
         [ 18_000, "Ekaterinburg", "Islamabad", "Karachi", "Tashkent" ],
         [ 19_800, "Chennai", "Kolkata", "Mumbai", "New Delhi" ],
         [ 20_700, "Kathmandu" ],
         [ 21_600, "Astana", "Dhaka", "Sri Jayawardenepura", "Almaty",
                   "Novosibirsk" ],
         [ 23_400, "Rangoon" ],
         [ 25_200, "Bangkok", "Hanoi", "Jakarta", "Krasnoyarsk" ],
         [ 28_800, "Beijing", "Chongqing", "Hong Kong", "Urumqi",
                   "Kuala Lumpur", "Singapore", "Taipei", "Perth", "Irkutsk",
                   "Ulaan Bataar" ],
         [ 32_400, "Seoul", "Osaka", "Sapporo", "Tokyo", "Yakutsk" ],
         [ 34_200, "Darwin", "Adelaide" ],
         [ 36_000, "Canberra", "Melbourne", "Sydney", "Brisbane", "Hobart",
                   "Vladivostok", "Guam", "Port Moresby" ],
         [ 39_600, "Magadan", "Solomon Is.", "New Caledonia" ],
         [ 43_200, "Fiji", "Kamchatka", "Marshall Is.", "Auckland",
                   "Wellington" ],
         [ 46_800, "Nuku'alofa" ]].
        each do |offset, *places|
          places.each { |place| @@zones << create(place, offset).freeze }
        end
        @@zones.sort!
      end
      @@zones
    end
create(name, offset)

Create a new TimeZone instance with the given name and offset.

[Source]

# File activesupport/lib/active_support/values/time_zone.rb, line 77
    def create(name, offset)
      zone = allocate
      zone.send!(:initialize, name, offset)
      zone
    end
new(name, utc_offset)

Create a new TimeZone object with the given name and offset. The offset is the number of seconds that this time zone is offset from UTC (GMT). Seconds were chosen as the offset unit because that is the unit that Ruby uses to represent time zone offsets (see Time#utc_offset).

[Source]

# File activesupport/lib/active_support/values/time_zone.rb, line 18
  def initialize(name, utc_offset)
    @name = name
    @utc_offset = utc_offset
  end
new(name)

Return a TimeZone instance with the given name, or nil if no such TimeZone instance exists. (This exists to support the use of this class with the composed_of macro.)

[Source]

# File activesupport/lib/active_support/values/time_zone.rb, line 86
    def new(name)
      self[name]
    end
us_zones()

A convenience method for returning a collection of TimeZone objects for time zones in the USA.

[Source]

# File activesupport/lib/active_support/values/time_zone.rb, line 176
    def us_zones
      all.find_all { |z| z.name =~ US_ZONES }
    end

Public Instance methods

<=>(zone)

Compare this time zone to the parameter. The two are comapred first on their offsets, and then by name.

[Source]

# File activesupport/lib/active_support/values/time_zone.rb, line 62
  def <=>(zone)
    result = (utc_offset <=> zone.utc_offset)
    result = (name <=> zone.name) if result == 0
    result
  end
adjust(time)

Adjust the given time to the time zone represented by self.

[Source]

# File activesupport/lib/active_support/values/time_zone.rb, line 47
  def adjust(time)
    time = time.to_time
    time + utc_offset - time.utc_offset
  end
formatted_offset( colon=true )

Returns the offset of this time zone as a formatted string, of the format "+HH:MM". If the offset is zero, this returns the empty string. If colon is false, a colon will not be inserted into the result.

[Source]

# File activesupport/lib/active_support/values/time_zone.rb, line 27
  def formatted_offset( colon=true )
    return "" if utc_offset == 0
    sign = (utc_offset < 0 ? -1 : 1)
    hours = utc_offset.abs / 3600
    minutes = (utc_offset.abs % 3600) / 60
    "%+03d%s%02d" % [ hours * sign, colon ? ":" : "", minutes ]
  end
now()

Compute and return the current time, in the time zone represented by self.

[Source]

# File activesupport/lib/active_support/values/time_zone.rb, line 37
  def now
    adjust(Time.now)
  end
to_s()

Returns a textual representation of this time zone.

[Source]

# File activesupport/lib/active_support/values/time_zone.rb, line 69
  def to_s
    "(GMT#{formatted_offset}) #{name}"
  end
today()

Return the current date in this time zone.

[Source]

# File activesupport/lib/active_support/values/time_zone.rb, line 42
  def today
    now.to_date
  end
unadjust(time)

Reinterprets the given time value as a time in the current time zone, and then adjusts it to return the corresponding time in the local time zone.

[Source]

# File activesupport/lib/active_support/values/time_zone.rb, line 55
  def unadjust(time)
    time = Time.local(*time.to_time.to_a)
    time - utc_offset + time.utc_offset
  end

[Validate]