Class: Statum::Machine

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

Overview

Class for representing event machine

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ Machine

Creates machine instance

Parameters:

  • options (Hash) —

    options hash

Options Hash (options):

  • field (Symbol) —

    Field to store state

  • initial (Symbol) —

    Initial state

  • states (Array<Symbol>) —

    States

  • events (Hash) —

    Events



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# File 'lib/statum/machine.rb', line 20

def initialize(options)
  @field   = options.delete(:field)
  @initial = options.delete(:initial)
  @states  = options.delete(:states)
  @events  = options.delete(:events)
end

Instance Attribute Details

#events ⇒ Hash (readonly)

Events

Returns:

  • (Hash) —

    the current value of events



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# File 'lib/statum/machine.rb', line 7

def events
  @events
end

#field ⇒ Symbol (readonly) Also known as: name

State field

Returns:

  • (Symbol) —

    the current value of field



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# File 'lib/statum/machine.rb', line 7

def field
  @field
end

#states ⇒ Array<Symbol> (readonly)

States

Returns:

  • (Array<Symbol>) —

    the current value of states



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# File 'lib/statum/machine.rb', line 7

def states
  @states
end

Instance Method Details

#current(instance) ⇒ Symbol

Returns current state of instance

Parameters:

  • instance (Object) —

    Instance of class

Returns:

  • (Symbol) —

    Current instance’s state



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# File 'lib/statum/machine.rb', line 72

def current(instance)
  value = instance.send(field)
  value.nil? ? @initial : value.to_sym
end

#event?(name) ⇒ Boolean

Checks if event present

Parameters:

  • name (Symbol) —

    event name

Returns:

  • (Boolean) 


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

def event?(name)
  @events.keys.include?(name.to_sym)
end

#fire!(instance, name) ⇒ Object

Execute an event

Parameters:

  • instance (Object) —

    Instance of class, that includes Statum

  • name (Symbol) —

    Event name

Raises:

  • Statum::UnknownEventError

  • Statum::ErrorTransitionError



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# File 'lib/statum/machine.rb', line 52

def fire!(instance, name)
  raise Statum::UnknownEventError, "Event #{name} not found" unless event?(name)

  current_state = current(instance)
  event         = events[name.to_sym]

  unless event.can_fire?(current_state)
    raise Statum::ErrorTransitionError, "Cannot transition from #{current_state} to #{event.to}"
  end

  event.before.evaluate(instance)
  instance.send("#{field}=", event.to)
  event.after.evaluate(instance)
end

#state?(name) ⇒ Boolean

Checks if state present

Parameters:

  • name (Symbol) —

    state name

Returns:

  • (Boolean) 


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# File 'lib/statum/machine.rb', line 32

def state?(name)
  @states.include?(name.to_sym)
end