Class: FSM::FSMState

Inherits:
Object
  • Object
show all
Defined in:
lib/barebone-fsm.rb

Overview

FSMState class represents a state of the finite state machine.

Usage

state = FSMState.new :state_name
state.event(:event_name) do # creates the event when block is given
  puts "#{@event} triggered on state #{@state}"
  :new_state
end  
puts state
state.event :event_name # triggers the event when block is absent

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(state_name) ⇒ FSMState

Returns a new instance of FSMState.



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# File 'lib/barebone-fsm.rb', line 38

def initialize(state_name) 
  @state = state_name
  @events = {}
end

Instance Attribute Details

#state ⇒ Object (readonly)

The readonly state variable represents an unique state. Though it can have any data type, usage of symbol or string is preferable.



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# File 'lib/barebone-fsm.rb', line 36

def state
  @state
end

Instance Method Details

#build(&build_block) ⇒ Object Also known as: run

The #build/#run method sets up the events as given in the build_block. Only event method is supported within the build_block with the name of the event and an optional block supplied. The operation for each such line is carried out by the #event method.



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# File 'lib/barebone-fsm.rb', line 68

def build(&build_block)
  self.instance_eval &build_block
end

#event(event_name, &event_block) ⇒ Object

When the event_block is provided, it sets up a new event for this state. Otherwise, when the event_block is missing, the event_name is triggered. If the event is nil or not already setup, then the default event is triggered.



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# File 'lib/barebone-fsm.rb', line 53

def event(event_name, &event_block)
  if event_name and block_given? then
    @events[event_name] = event_block
  elsif event_name and @events.has_key? event_name then
    @event = event_name
    self.instance_eval &@events[@event]
  elsif @events.has_key? :default then
    @event = :default
    self.instance_eval &@events[@event]
  end
end

#to_s ⇒ Object 



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# File 'lib/barebone-fsm.rb', line 43

def to_s() 
  @state.to_s + 
    ": [" + 
      @events.keys.map(&:to_s).join(', ') + 
    "]" 
end