Class: MicroMachine

Inherits:
Object
  • Object
show all
Defined in:
lib/micromachine.rb

Constant Summary collapse

InvalidEvent = 
Class.new(NoMethodError)
InvalidState = 
Class.new(ArgumentError)

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(initial_state) ⇒ MicroMachine

Returns a new instance of MicroMachine.



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# File 'lib/micromachine.rb', line 8

def initialize(initial_state)
  @state = initial_state
  @transitions_for = Hash.new
  @callbacks = Hash.new { |hash, key| hash[key] = [] }
end

Instance Attribute Details

#state ⇒ Object (readonly)

Returns the value of attribute state.



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# File 'lib/micromachine.rb', line 6

def state
  @state
end

#transitions_for ⇒ Object (readonly)

Returns the value of attribute transitions_for.



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# File 'lib/micromachine.rb', line 5

def transitions_for
  @transitions_for
end

Instance Method Details

#==(some_state) ⇒ Object 



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# File 'lib/micromachine.rb', line 54

def ==(some_state)
  state == some_state
end

#events ⇒ Object 



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# File 'lib/micromachine.rb', line 46

def events
  transitions_for.keys
end

#on(key, &block) ⇒ Object 



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# File 'lib/micromachine.rb', line 14

def on(key, &block)
  @callbacks[key] << block
end

#states ⇒ Object 



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# File 'lib/micromachine.rb', line 50

def states
  events.map { |e| transitions_for[e].to_a }.flatten.uniq
end

#trigger(event) ⇒ Object 



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# File 'lib/micromachine.rb', line 22

def trigger(event)
  if trigger?(event)
    @state = transitions_for[event][@state]
    callbacks = @callbacks[@state] + @callbacks[:any]
    callbacks.each { |callback| callback.call(event) }
    true
  else
    false
  end
end

#trigger!(event) ⇒ Object 



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# File 'lib/micromachine.rb', line 33

def trigger!(event)
  if trigger(event)
    true
  else
    raise InvalidState.new("Event '#{event}' not valid from state '#{@state}'")
  end
end

#trigger?(event) ⇒ Boolean

Returns:

  • (Boolean)

Raises:



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# File 'lib/micromachine.rb', line 41

def trigger?(event)
  raise InvalidEvent unless transitions_for.has_key?(event)
  transitions_for[event][state] ? true : false
end

#when(event, transitions) ⇒ Object 



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# File 'lib/micromachine.rb', line 18

def when(event, transitions)
  transitions_for[event] = transitions
end