Class: Finity::Machine

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(klass, options = {}, &block) ⇒ Machine

Initialize a new state machine within the provided class and define methods for querying the current state and initiating transitions.



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# File 'lib/finity/machine.rb', line 29

def initialize klass, options = {}, &block
  @klass, @states, @events, @init = klass, {}, {}, options.delete(:init)
  @klass.send :define_method, :event! do |*args|
    klass.machine.update self, *args
  end
  @klass.send :define_method, :state? do |*args|
    klass.machine.current.name.eql? *args
  end
  instance_eval &block if block_given?
end

Instance Attribute Details

#current ⇒ Object

Returns the value of attribute current.



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# File 'lib/finity/machine.rb', line 25

def current
  @current
end

#events ⇒ Object

Returns the value of attribute events.



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# File 'lib/finity/machine.rb', line 25

def events
  @events
end

#states ⇒ Object

Returns the value of attribute states.



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# File 'lib/finity/machine.rb', line 25

def states
  @states
end

Instance Method Details

#event(name, options = {}, &block) ⇒ Object

Register an event and evaluate the block for transitions.



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# File 'lib/finity/machine.rb', line 51

def event name, options = {}, &block
  @events[name] = Event.new name, options, &block
end

#init ⇒ Object

Return the name of the initial state.



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# File 'lib/finity/machine.rb', line 41

def init
  @init ||= @states.keys.first unless @states.first.nil?
end

#state(name, options = {}) ⇒ Object

Register a state.



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# File 'lib/finity/machine.rb', line 46

def state name, options = {}
  @states[name] = State.new name, options
end

#update(object, event) ⇒ Object

An event occured, so update the state machine by evaluating the transition functions and notify the left and entered state.



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# File 'lib/finity/machine.rb', line 57

def update object, event
  @current ||= @states[init]
  if (state = @events[event].handle object, @current)
    if @states[state].nil?
      raise InvalidState, "Invalid state '#{state}'"
    end
    @current.leave object
    @current = @states[state]
    @current.enter object
  end
end