# File lib/active_model/attribute_methods.rb, line 225 def alias_attribute(new_name, old_name) attribute_method_matchers.each do |matcher| module_eval def #{matcher.method_name(new_name)}(*args) send(:#{matcher.method_name(old_name)}, *args) end, __FILE__, __LINE__ + 1 end 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 lib/active_model/attribute_methods.rb, line 220 def attribute_method_affix(*affixes) attribute_method_matchers.concat(affixes.map { |affix| AttributeMethodMatcher.new :prefix => affix[:prefix], :suffix => affix[:suffix] }) undefine_attribute_methods 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
# File lib/active_model/attribute_methods.rb, line 145 def attribute_method_prefix(*prefixes) attribute_method_matchers.concat(prefixes.map { |prefix| AttributeMethodMatcher.new :prefix => prefix }) undefine_attribute_methods end
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 lib/active_model/attribute_methods.rb, line 182 def attribute_method_suffix(*suffixes) attribute_method_matchers.concat(suffixes.map { |suffix| AttributeMethodMatcher.new :suffix => suffix }) undefine_attribute_methods end
Returns true if the attribute methods defined have been generated.
# File lib/active_model/attribute_methods.rb, line 304 def attribute_methods_generated? @attribute_methods_generated ||= nil end
Defines an “attribute” method (like inheritance_column or table_name). A new (class) method will be created with the given name. If a value is specified, the new method will return that value (as a string). Otherwise, the given block will be used to compute the value of the method.
The original method will be aliased, with the new name being prefixed with “original_”. This allows the new method to access the original value.
Example:
class Person include ActiveModel::AttributeMethods cattr_accessor :primary_key cattr_accessor :inheritance_column define_attr_method :primary_key, "sysid" define_attr_method( :inheritance_column ) do original_inheritance_column + "_id" end end
Provides you with:
AttributePerson.primary_key # => "sysid" AttributePerson.inheritance_column = 'address' AttributePerson.inheritance_column # => 'address_id'
# File lib/active_model/attribute_methods.rb, line 93 def define_attr_method(name, value=nil, &block) sing = singleton_class sing.class_eval if method_defined?(:original_#{name}) undef :original_#{name} end alias_method :original_#{name}, :#{name}, __FILE__, __LINE__ + 1 if block_given? sing.send :define_method, name, &block else # use eval instead of a block to work around a memory leak in dev # mode in fcgi sing.class_eval def #{name}; #{value.to_s.inspect}; end, __FILE__, __LINE__ + 1 end end
Declares a 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
# File lib/active_model/attribute_methods.rb, line 259 def define_attribute_methods(attr_names) return if attribute_methods_generated? attr_names.each do |attr_name| attribute_method_matchers.each do |matcher| unless instance_method_already_implemented?(matcher.method_name(attr_name)) generate_method = "define_method_#{matcher.prefix}attribute#{matcher.suffix}" if respond_to?(generate_method) send(generate_method, attr_name) else method_name = matcher.method_name(attr_name) generated_attribute_methods.module_eval if method_defined?(:#{method_name}) undef :#{method_name} end def #{method_name}(*args) send(:#{matcher.method_missing_target}, '#{attr_name}', *args) end, __FILE__, __LINE__ + 1 end end end end @attribute_methods_generated = true end
Removes all the previously dynamically defined methods from the class
# File lib/active_model/attribute_methods.rb, line 287 def undefine_attribute_methods generated_attribute_methods.module_eval do instance_methods.each { |m| undef_method(m) } end @attribute_methods_generated = nil end
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