Module: ActiveModel::AttributeMethods::ClassMethods
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Classes:
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Defined in: | activemodel/lib/active_model/attribute_methods.rb |
Instance Method Summary
-
#alias_attribute(new_name, old_name)
Allows you to make aliases for attributes.
-
#attribute_alias(name)
Returns the original name for the alias
name
-
#attribute_alias?(new_name) ⇒ Boolean
Is
new_name
an alias? -
#attribute_method_affix(*affixes)
Declares a method available for all attributes with the given prefix and suffix.
-
#attribute_method_prefix(*prefixes, parameters: nil)
Declares a method available for all attributes with the given prefix.
-
#attribute_method_suffix(*suffixes, parameters: nil)
Declares a method available for all attributes with the given suffix.
-
#define_attribute_method(attr_name, _owner: generated_attribute_methods, as: attr_name)
Declares an attribute that should be prefixed and suffixed by
::ActiveModel::AttributeMethods
. -
#define_attribute_methods(*attr_names)
Declares the attributes that should be prefixed and suffixed by
::ActiveModel::AttributeMethods
. -
#undefine_attribute_methods
Removes all the previously dynamically defined methods from the class, including alias attribute methods.
Instance Method Details
#alias_attribute(new_name, old_name)
Allows you to make aliases for attributes.
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_suffix '_short?'
define_attribute_methods :name
alias_attribute :nickname, :name
private
def attribute_short?(attr)
send(attr).length < 5
end
end
person = Person.new
person.name = 'Bob'
person.name # => "Bob"
person.nickname # => "Bob"
person.name_short? # => true
person.nickname_short? # => true
# File 'activemodel/lib/active_model/attribute_methods.rb', line 204
def alias_attribute(new_name, old_name) old_name = old_name.to_s new_name = new_name.to_s self.attribute_aliases = attribute_aliases.merge(new_name => old_name) aliases_by_attribute_name[old_name] << new_name eagerly_generate_alias_attribute_methods(new_name, old_name) end
#attribute_alias(name)
Returns the original name for the alias name
# File 'activemodel/lib/active_model/attribute_methods.rb', line 261
def attribute_alias(name) attribute_aliases[name.to_s] end
#attribute_alias?(new_name) ⇒ Boolean
Is new_name
an alias?
# File 'activemodel/lib/active_model/attribute_methods.rb', line 256
def attribute_alias?(new_name) attribute_aliases.key? new_name.to_s end
#attribute_method_affix(*affixes)
Declares a method available for all attributes with the given prefix and suffix. Uses ActiveModel::AttributeMethods#method_missing and ActiveModel::AttributeMethods#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.
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)
send("#{attr}=", 'Default Name')
end
end
person = Person.new
person.name # => 'Gem'
person.reset_name_to_default!
person.name # => 'Default Name'
# File 'activemodel/lib/active_model/attribute_methods.rb', line 176
def attribute_method_affix(*affixes) self.attribute_method_patterns += affixes.map! { |affix| AttributeMethodPattern.new(**affix) } undefine_attribute_methods end
#attribute_method_prefix(*prefixes, parameters: nil)
Declares a method available for all attributes with the given prefix. Uses ActiveModel::AttributeMethods#method_missing and ActiveModel::AttributeMethods#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.
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
# File 'activemodel/lib/active_model/attribute_methods.rb', line 107
def attribute_method_prefix(*prefixes, parameters: nil) self.attribute_method_patterns += prefixes.map! { |prefix| AttributeMethodPattern.new(prefix: prefix, parameters: parameters) } undefine_attribute_methods end
#attribute_method_suffix(*suffixes, parameters: nil)
Declares a method available for all attributes with the given suffix. Uses ActiveModel::AttributeMethods#method_missing and ActiveModel::AttributeMethods#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.
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 141
def attribute_method_suffix(*suffixes, parameters: nil) self.attribute_method_patterns += suffixes.map! { |suffix| AttributeMethodPattern.new(suffix: suffix, parameters: parameters) } undefine_attribute_methods end
#define_attribute_method(attr_name, _owner: generated_attribute_methods, as: attr_name)
Declares an attribute that should be prefixed and suffixed by ::ActiveModel::AttributeMethods
.
To use, pass an attribute name (as string or symbol). Be sure to declare define_attribute_method
after you define any prefix, suffix or affix method, or they will not hook in.
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_suffix '_short?'
# Call to define_attribute_method must appear after the
# attribute_method_prefix, attribute_method_suffix or
# attribute_method_affix declarations.
define_attribute_method :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 327
def define_attribute_method(attr_name, _owner: generated_attribute_methods, as: attr_name) ActiveSupport::CodeGenerator.batch(_owner, __FILE__, __LINE__) do |owner| attribute_method_patterns.each do |pattern| define_attribute_method_pattern(pattern, attr_name, owner: owner, as: as) end attribute_method_patterns_cache.clear end end
#define_attribute_methods(*attr_names)
Declares the attributes that should be prefixed and suffixed by ::ActiveModel::AttributeMethods
.
To use, pass 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 declarations.
define_attribute_methods :name, :age, :address
private
def clear_attribute(attr)
send("#{attr}=", nil)
end
end
# File 'activemodel/lib/active_model/attribute_methods.rb', line 288
def define_attribute_methods(*attr_names) ActiveSupport::CodeGenerator.batch(generated_attribute_methods, __FILE__, __LINE__) do |owner| attr_names.flatten.each do |attr_name| define_attribute_method(attr_name, _owner: owner) aliases_by_attribute_name[attr_name.to_s].each do |aliased_name| generate_alias_attribute_methods owner, aliased_name, attr_name end end end end
#undefine_attribute_methods
Removes all the previously dynamically defined methods from the class, including alias attribute methods.
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_suffix '_short?'
define_attribute_method :name
alias_attribute :first_name, :name
private
def attribute_short?(attr)
send(attr).length < 5
end
end
person = Person.new
person.name = 'Bob'
person.first_name # => "Bob"
person.name_short? # => true
Person.undefine_attribute_methods
person.name_short? # => NoMethodError
person.first_name # => NoMethodError
# File 'activemodel/lib/active_model/attribute_methods.rb', line 390
def undefine_attribute_methods generated_attribute_methods.module_eval do undef_method(*instance_methods) end attribute_method_patterns_cache.clear end