我目前有一个超类,它有一个功能,我希望所有的子类在它的每个功能内调用.该函数应该在rails中表现得像一个before_filter函数,但我不知道如何执行before_filter.这是一个例子
class Superclass
def before_each_method
puts "Before Method" #this is supposed to be invoked by each extending class' method
end
end
class Subclass < Superclass
def my_method
#when this method is called,before_each_method method is supposed to get invoked
end
end
解决方法
这是一种方法：
class Superclass
def before_each_method name
p [:before_method,name]
end
def self.method_added name
return if @__last_methods_added && @__last_methods_added.include?(name)
with = :"#{name}_with_before_each_method"
without = :"#{name}_without_before_each_method"
@__last_methods_added = [name,with,without]
define_method with do |*args,&block|
before_each_method name
send without,*args,&block
end
alias_method without,name
alias_method name,with
@__last_methods_added = nil
end
end
class SubclassA < Superclass
def my_new_method
p :my_new_method
end
def my_new_other_method
p :my_new_other_method
end
end
SubclassA.new.my_new_method
SubclassA.new.my_new_other_method