Declare and check for suffixed attribute methods.

Methods
A
M
Instance Public methods
attribute_method_suffix(*suffixes)

Declare a method available for all attributes with the given suffix. Uses method_missing and respond_to? to rewrite the method

#{attr}#{suffix}(*args, &block)

to

attribute#{suffix}(#{attr}, *args, &block)

An attribute#{suffix} instance method must exist and accept at least the attr argument.

For example:

class Person < ActiveRecord::Base
  attribute_method_suffix '_changed?'

  private
    def attribute_changed?(attr)
      ...
    end
end

person = Person.find(1)
person.name_changed?    # => false
person.name = 'Hubert'
person.name_changed?    # => true

Source: show 

# File rails/activerecord/lib/active_record/attribute_methods.rb, line 35
def attribute_method_suffix(*suffixes)
  attribute_method_suffixes.concat suffixes
  rebuild_attribute_method_regexp
end
match_attribute_method?(method_name)

Returns MatchData if method_name is an attribute method.

Source: show 

# File rails/activerecord/lib/active_record/attribute_methods.rb, line 41
def match_attribute_method?(method_name)
  rebuild_attribute_method_regexp unless defined?(@@attribute_method_regexp) && @@attribute_method_regexp
  @@attribute_method_regexp.match(method_name)
end