Class: FiniteMachine::Transition Private

Inherits:
Object
  • Object
show all
Includes:
Threadable
Defined in:
lib/finite_machine/transition.rb

Overview

This class is part of a private API. You should avoid using this class if possible, as it may be removed or be changed in the future.

Class describing a transition associated with a given event

The Transition is created with the ‘event` helper.

Examples:

Converting event into Transition

event :go, :red => :green

will be translated to

Transition.new(context, :go, {states: {:red => :green}})

Instance Method Summary collapse

Constructor Details

#initialize(context, name, attrs = {}) ⇒ Transition

Initialize a Transition

Examples:

attributes = {states: {green: :yellow}}
Transition.new(context, :go, attributes)


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# File 'lib/finite_machine/transition.rb', line 48

def initialize(context, name, attrs = {})
  @context     = context
  @name        = name
  @states      = attrs.fetch(:states, {})
  @if          = Array(attrs.fetch(:if, []))
  @unless      = Array(attrs.fetch(:unless, []))
  @conditions  = make_conditions
  freeze
end

Instance Method Details

#check_conditions(*args) ⇒ Boolean

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Verify conditions returning true if all match, false otherwise



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# File 'lib/finite_machine/transition.rb', line 76

def check_conditions(*args)
  conditions.all? do |condition|
    condition.call(context, *args)
  end
end

#inspect ⇒ String

Return string representation



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# File 'lib/finite_machine/transition.rb', line 134

def inspect
  transitions = @states.map { |from, to| "#{from} -> #{to}" }.join(", ")
  "<##{self.class} @name=#{@name}, @transitions=#{transitions}, " \
    "@when=#{@conditions}>"
end

#make_conditions ⇒ Array[Callable]

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Reduce conditions



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# File 'lib/finite_machine/transition.rb', line 63

def make_conditions
  @if.map { |c| Callable.new(c) } +
    @unless.map { |c| Callable.new(c).invert }
end

#matches?(from) ⇒ Boolean

Check if this transition matches from state

Examples:

transition = Transition.new(context, states: {:green => :red})
transition.matches?(:green) # => true


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# File 'lib/finite_machine/transition.rb', line 95

def matches?(from)
  states.keys.any? { |state| [ANY_STATE, from].include?(state) }
end

#to_s ⇒ String

Return transition name

Examples:

transition = Transition.new(context, name: :go)
transition.to_s # => "go"


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# File 'lib/finite_machine/transition.rb', line 125

def to_s
  @name.to_s
end

#to_state(from) ⇒ Symbol

Find to state for this transition given the from state

Examples:

transition = Transition.new(context, states: {:green => :red})
transition.to_state(:green) # => :red


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# File 'lib/finite_machine/transition.rb', line 112

def to_state(from)
  states[from] || states[ANY_STATE]
end