Class | StateMachine::Transition |
In: |
lib/state_machine/transition.rb
|
Parent: | Object |
args | [RW] | The arguments passed in to the event that triggered the transition (does not include the run_action boolean argument if specified) |
from | [R] | The original state value before the transition |
machine | [R] | The state machine for which this transition is defined |
object | [R] | The object being transitioned |
result | [R] | The result of invoking the action associated with the machine |
to | [R] | The new state value after the transition |
transient | [W] | Whether the transition is only existing temporarily for the object |
Determines equality of transitions by testing whether the object, states, and event involved in the transition are equal
# File lib/state_machine/transition.rb, line 313 313: def ==(other) 314: other.instance_of?(self.class) && 315: other.object == object && 316: other.machine == machine && 317: other.from_name == from_name && 318: other.to_name == to_name && 319: other.event == event 320: end
A hash of all the core attributes defined for this transition with their names as keys and values of the attributes as values.
machine = StateMachine.new(Vehicle) transition = StateMachine::Transition.new(Vehicle.new, machine, :ignite, :parked, :idling) transition.attributes # => {:object => #<Vehicle:0xb7d60ea4>, :attribute => :state, :event => :ignite, :from => 'parked', :to => 'idling'}
# File lib/state_machine/transition.rb, line 185 185: def attributes 186: @attributes ||= {:object => object, :attribute => attribute, :event => event, :from => from, :to => to} 187: end
The state name before the transition
# File lib/state_machine/transition.rb, line 129 129: def from_name 130: @from_state.name 131: end
The human-readable state name before the transition
# File lib/state_machine/transition.rb, line 139 139: def human_from_name 140: @from_state.human_name(@object.class) 141: end
The new human-readable state name after the transition
# File lib/state_machine/transition.rb, line 154 154: def human_to_name 155: @to_state.human_name(@object.class) 156: end
Generates a nicely formatted description of this transitions‘s contents.
For example,
transition = StateMachine::Transition.new(object, machine, :ignite, :parked, :idling) transition # => #<StateMachine::Transition attribute=:state event=:ignite from="parked" from_name=:parked to="idling" to_name=:idling>
# File lib/state_machine/transition.rb, line 328 328: def inspect 329: "#<#{self.class} #{%w(attribute event from from_name to to_name).map {|attr| "#{attr}=#{send(attr).inspect}"} * ' '}>" 330: end
Does this transition represent a loopback (i.e. the from and to state are the same)
machine = StateMachine.new(Vehicle) StateMachine::Transition.new(Vehicle.new, machine, :park, :parked, :parked).loopback? # => true StateMachine::Transition.new(Vehicle.new, machine, :park, :idling, :parked).loopback? # => false
# File lib/state_machine/transition.rb, line 166 166: def loopback? 167: from_name == to_name 168: end
Runs the actual transition and any before/after callbacks associated with the transition. The action associated with the transition/machine can be skipped by passing in false.
class Vehicle state_machine :action => :save do ... end end vehicle = Vehicle.new transition = StateMachine::Transition.new(vehicle, machine, :ignite, :parked, :idling) transition.perform # => Runs the +save+ action after setting the state attribute transition.perform(false) # => Only sets the state attribute transition.perform(Time.now) # => Passes in additional arguments and runs the +save+ action transition.perform(Time.now, false) # => Passes in additional arguments and only sets the state attribute
# File lib/state_machine/transition.rb, line 207 207: def perform(*args) 208: run_action = [true, false].include?(args.last) ? args.pop : true 209: self.args = args 210: 211: # Run the transition 212: !!TransitionCollection.new([self], :actions => run_action).perform 213: end
Transitions the current value of the state to that specified by the transition. Once the state is persisted, it cannot be persisted again until this transition is reset.
class Vehicle state_machine do event :ignite do transition :parked => :idling end end end vehicle = Vehicle.new transition = StateMachine::Transition.new(vehicle, Vehicle.state_machine, :ignite, :parked, :idling) transition.persist vehicle.state # => 'idling'
# File lib/state_machine/transition.rb, line 268 268: def persist 269: unless @persisted 270: machine.write(object, :state, to) 271: @persisted = true 272: end 273: end
The fully-qualified state name before the transition
# File lib/state_machine/transition.rb, line 134 134: def qualified_from_name 135: @from_state.qualified_name 136: end
The new fully-qualified state name after the transition
# File lib/state_machine/transition.rb, line 149 149: def qualified_to_name 150: @to_state.qualified_name 151: end
Resets any tracking of which callbacks have already been run and whether the state has already been persisted
# File lib/state_machine/transition.rb, line 306 306: def reset 307: @before_run = @persisted = @after_run = false 308: @paused_block = nil 309: end
Rolls back changes made to the object‘s state via this transition. This will revert the state back to the from value.
class Vehicle state_machine :initial => :parked do event :ignite do transition :parked => :idling end end end vehicle = Vehicle.new # => #<Vehicle:0xb7b7f568 @state="parked"> transition = StateMachine::Transition.new(vehicle, Vehicle.state_machine, :ignite, :parked, :idling) # Persist the new state vehicle.state # => "parked" transition.persist vehicle.state # => "idling" # Roll back to the original state transition.rollback vehicle.state # => "parked"
# File lib/state_machine/transition.rb, line 299 299: def rollback 300: reset 301: machine.write(object, :state, from) 302: end
Runs the before / after callbacks for this transition. If a block is provided, then it will be executed between the before and after callbacks.
Configuration options:
This will return true if all before callbacks gets executed. After callbacks will not have an effect on the result.
# File lib/state_machine/transition.rb, line 235 235: def run_callbacks(options = {}, &block) 236: options = {:before => true, :after => true}.merge(options) 237: @success = false 238: 239: halted = pausable { before(options[:after], &block) } if options[:before] 240: 241: # After callbacks are only run if: 242: # * An around callback didn't halt after yielding 243: # * They're enabled or the run didn't succeed 244: after if !(@before_run && halted) && (options[:after] || !@success) 245: 246: @before_run 247: end
The new state name after the transition
# File lib/state_machine/transition.rb, line 144 144: def to_name 145: @to_state.name 146: end
Runs a block within a transaction for the object being transitioned. By default, transactions are a no-op unless otherwise defined by the machine‘s integration.
# File lib/state_machine/transition.rb, line 218 218: def within_transaction 219: machine.within_transaction(object) do 220: yield 221: end 222: end