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# File activemodel/lib/active_model/attribute_methods.rb, line 225 225: def alias_attribute(new_name, old_name) 226: attribute_method_matchers.each do |matcher| 227: matcher_new = matcher.method_name(new_name).to_s 228: matcher_old = matcher.method_name(old_name).to_s 229: define_optimized_call self, matcher_new, matcher_old 230: end 231: end
Declares a method available for all attributes with the given prefix and suffix. Uses method_missing and respond_to? to rewrite the method.
#{prefix}#{attr}#{suffix}(*args, &block)
to
#{prefix}attribute#{suffix}(#{attr}, *args, &block)
An #{prefix}attribute#{suffix} instance method must exist and accept at least the attr argument.
For example:
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_affix :prefix => 'reset_', :suffix => '_to_default!'
define_attribute_methods [:name]
private
def reset_attribute_to_default!(attr)
...
end
end
person = Person.new
person.name # => 'Gem'
person.reset_name_to_default!
person.name # => 'Gemma'
# File activemodel/lib/active_model/attribute_methods.rb, line 220 220: def attribute_method_affix(*affixes) 221: self.attribute_method_matchers += affixes.map { |affix| AttributeMethodMatcher.new :prefix => affix[:prefix], :suffix => affix[:suffix] } 222: undefine_attribute_methods 223: end
Declares a method available for all attributes with the given prefix. Uses method_missing and respond_to? to rewrite the method.
#{prefix}#{attr}(*args, &block)
to
#{prefix}attribute(#{attr}, *args, &block)
An instance method #{prefix}attribute must exist and accept at least the attr argument.
For example:
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_prefix 'clear_'
define_attribute_methods [:name]
private
def clear_attribute(attr)
send("#{attr}=", nil)
end
end
person = Person.new
person.name = "Bob"
person.name # => "Bob"
person.clear_name
person.name # => nil
Declares 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
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_suffix '_short?'
define_attribute_methods [:name]
private
def attribute_short?(attr)
send(attr).length < 5
end
end
person = Person.new
person.name = "Bob"
person.name # => "Bob"
person.name_short? # => true
# File activemodel/lib/active_model/attribute_methods.rb, line 261 261: def define_attribute_method(attr_name) 262: attribute_method_matchers.each do |matcher| 263: method_name = matcher.method_name(attr_name) 264: 265: unless instance_method_already_implemented?(method_name) 266: generate_method = "define_method_#{matcher.method_missing_target}" 267: 268: if respond_to?(generate_method, true) 269: send(generate_method, attr_name) 270: else 271: define_optimized_call generated_attribute_methods, method_name, matcher.method_missing_target, attr_name.to_s 272: end 273: end 274: end 275: attribute_method_matchers_cache.clear 276: end
Declares the attributes that should be prefixed and suffixed by ActiveModel::AttributeMethods.
To use, pass in an array of attribute names (as strings or symbols), be sure to declare define_attribute_methods after you define any prefix, suffix or affix methods, or they will not hook in.
class Person
include ActiveModel::AttributeMethods
attr_accessor :name, :age, :address
attribute_method_prefix 'clear_'
# Call to define_attribute_methods must appear after the
# attribute_method_prefix, attribute_method_suffix or
# attribute_method_affix declares.
define_attribute_methods [:name, :age, :address]
private
def clear_attribute(attr)
...
end
end
Removes all the previously dynamically defined methods from the class