LinearWorkFlow
LinearWorkFlow
is a basic state machine for managing state change through a
single linear set of states. That is, there is only one valid sequence of states
and the work flow is either forward or backward through those steps.
Installation
Add this line to your application's Gemfile:
gem 'linear_work_flow'
And then execute:
$ bundle
Or install it yourself as:
$ gem install linear_work_flow
Usage
Define a new work flow
To create a new linear work flow, create a new class that inherits from
LinearWorkFlow::WorkFlow
with a class method states
that defines the series
of steps as an array, in the order the states are to be traversed.
class WorkFlow < LinearWorkFlow::WorkFlow
def self.states
[:one, :two, :three, :four]
end
end
Use the work flow
A new instance of WorkFlow
will be created via new
and will have its state
set as the first state as defined in WorkFlow.states
.
work_flow = WorkFlow.new
work_flow.state == :one
Changing state
Use the methods forward!
and back!
to change state.
work_flow.forward!
work_flow.state == :two
work_flow.forward!
work_flow.state == :three
work_flow.back!
work_flow.state == :two
Check first and last
first?
and last?
methods can be used to check if the work flow is at the beginning or
end of the defined states.
work_flow = WorkFlow.new
work_flow.first? == true
work_flow.last? == false
Initiate at a particular state
A work flow can be initiate at a particular state.
last_state = WorkFlow.states.last
work_flow = WorkFlow.at last_state
work_flow.state == last_state == :four
work_flow.last? == true
Check whether a state can be changed
Use the can?
method to check whether a work flow can be move forward or back.
work_flow = WorkFlow.new
work_flow.can?(:back) == false
work_flow.can?(:forward) == true
work_flow.forward!
work_flow.can?(:back) == true