我想对 pluginaweek 状态机(https://github.com/pluginaweek/state_machine)进行猴子补丁,以便我可以从 mixin 模块将代码注入状态机。有谁知道如何在状态机中定义一个新方法来做到这一点?或者,也许有更好的方法来做我想要完成的事情?
假设,
class Artifact < ActiveRecord::Base
include Provisionable # << This module makes the magic method 'provision',
# << below, available
state_machine :machine_state, :initial => :s_initial do
# ...
provision(:param1, :param2, :param3) # << The Question: how to define
# << this in the Provisionable mixin
# << module, below
...
end
...
end
module Provisionable
#
# << provision() is supposed to inject the desired code into the state machine:
#
def provision
# << Code sample to be injected begins here:
event :parameterize do
transition :s_unprovisioned => :s_initial
end
before_transition :s_unprovisioned => :s_initial do |artifact, transition|
transition.args.each_pair do |param, value|
# etc...
end
end
# >> Code to be injected ends here.
end
end
对于那些购买状态机的人,我强烈推荐这个。
谢谢!
[稍后添加:]我制定了一个解决方案,希望对其他人有所帮助。我没有混入一个模块,而是修改了 state_machine 以添加实例方法来注入代码。
StateMachine::Machine.class_eval do
def inject_provisioning()
event :start do
transition :s_initial => :s_provisioning
end
after_transition :s_initial => :s_provisioning do |goal, transition|
# Do useful stuff here
true
end
event :provision do
transition :s_provisioning => :s_completed
end
before_transition :s_provisioning => :s_completed do |goal, transition|
artifact_type = transition.args[0]
params = transition.args[1]
# Useful stuff here
true
end
after_transition :s_provisioning => :s_completed do |goal, transition|
artifact_type = transition.args[0]
params = transition.args[1]
# Useful stuff here
end
end
def inject_expiration()
event :chron do
expired_callback = lambda \
do |goal|
return false if goal.expires_at == :never
goal.expires_at.to_i < DateTime.now.to_i
end
active_callback = lambda \
do |goal|
return true if goal.expires_at == :never
goal.expires_at.to_i >= DateTime.now.to_i
end
transition all - :s_expired => :s_expired, :if => expired_callback
end
before_transition all - :s_expired => :s_expired do |goal, transition|
goal.undo
end
end
现在,当我在类中打开 state_machine 定义时,我可以进行简单的类似宏的调用来注入代码:
state_machine :machine_state, :initial => :s_initial do
inject_provisioning
inject_expiration
end
希望其他人觉得这很有用。