Class: ULID::MonotonicGenerator

Inherits:
Object
  • Object
show all
Includes:
MonitorMixin
Defined in:
lib/ulid/monotonic_generator.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ MonotonicGenerator

Returns a new instance of MonotonicGenerator.



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# File 'lib/ulid/monotonic_generator.rb', line 22

def initialize
  super
  @last = nil
end

Instance Attribute Details

#last ⇒ ULID?

Returns:



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# File 'lib/ulid/monotonic_generator.rb', line 17

def last
  @last
end

Instance Method Details

#encode(moment: Utils.current_milliseconds) ⇒ String

Just providing similar api as ‘ULID.generate` and `ULID.encode` relation. No performance benefit exists in monotonic generator’s one.

Parameters:

  • moment (Time, Integer) (defaults to: Utils.current_milliseconds)

Returns:

  • (String)

See Also:



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# File 'lib/ulid/monotonic_generator.rb', line 80

def encode(moment: Utils.current_milliseconds)
  generate(moment:).encode
end

#freeze ⇒ void

This method returns an undefined value.

Raises:

  • (TypeError) —

    always raises exception and does not freeze self



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# File 'lib/ulid/monotonic_generator.rb', line 88

def freeze
  raise(TypeError, "cannot freeze #{self.class}")
end

#generate(moment: Utils.current_milliseconds) ⇒ ULID

Parameters:

  • moment (Time, Integer) (defaults to: Utils.current_milliseconds)

Returns:

Raises:

  • (OverflowError) —

    if the entropy part is larger than the ULID limit in same milliseconds

  • (UnexpectedError) —

    if the generated ULID is an invalid value in monotonicity spec. Basically will not happen. Just means this feature prefers error rather than invalid value.



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# File 'lib/ulid/monotonic_generator.rb', line 38

def generate(moment: Utils.current_milliseconds)
  synchronize do
    prev = @last
    unless prev
      ret = ULID.generate(moment:)
      @last = ret
      return ret
    end

    milliseconds = Utils.milliseconds_from_moment(moment)

    ulid = (
      if prev.milliseconds < milliseconds
        ULID.generate(moment: milliseconds)
      else
        ULID.generate(moment: prev.milliseconds, entropy: prev.entropy.succ)
      end
    )

    unless ulid > prev
      base_message = "monotonicity broken from unexpected reasons # generated: #{ulid.inspect}, prev: #{prev.inspect}"
      additional_information = (
        if Thread.list == [Thread.main]
          '# NOTE: looks single thread only exist'
        else
          '# NOTE: ran on multi threads, so this might from concurrency issue'
        end
      )

      raise(UnexpectedError, base_message + additional_information)
    end

    @last = ulid
    ulid
  end
end

#inspect ⇒ String Also known as: to_s

Returns:

  • (String) 


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# File 'lib/ulid/monotonic_generator.rb', line 28

def inspect
  "ULID::MonotonicGenerator(last: #{@last.inspect})"
end