# File lib/active_model/attribute_methods.rb, line 225 225: def alias_attribute(new_name, old_name) 226: attribute_method_matchers.each do |matcher| 227: module_eval def #{matcher.method_name(new_name)}(*args) send(:#{matcher.method_name(old_name)}, *args) end, __FILE__, __LINE__ + 1 228: end 229: 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 220 220: def attribute_method_affix(*affixes) 221: attribute_method_matchers.concat(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
# File lib/active_model/attribute_methods.rb, line 145 145: def attribute_method_prefix(*prefixes) 146: attribute_method_matchers.concat(prefixes.map { |prefix| AttributeMethodMatcher.new :prefix => prefix }) 147: undefine_attribute_methods 148: 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 182 182: def attribute_method_suffix(*suffixes) 183: attribute_method_matchers.concat(suffixes.map { |suffix| AttributeMethodMatcher.new :suffix => suffix }) 184: undefine_attribute_methods 185: end
Returns true if the attribute methods defined have been generated.
# File lib/active_model/attribute_methods.rb, line 304 304: def attribute_methods_generated? 305: @attribute_methods_generated ||= nil 306: 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 93: def define_attr_method(name, value=nil, &block) 94: sing = singleton_class 95: sing.class_eval if method_defined?(:original_#{name}) undef :original_#{name} end alias_method :original_#{name}, :#{name}, __FILE__, __LINE__ + 1 96: if block_given? 97: sing.send :define_method, name, &block 98: else 99: # use eval instead of a block to work around a memory leak in dev 100: # mode in fcgi 101: sing.class_eval def #{name}; #{value.to_s.inspect}; end, __FILE__, __LINE__ + 1 102: end 103: 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 259 259: def define_attribute_methods(attr_names) 260: return if attribute_methods_generated? 261: attr_names.each do |attr_name| 262: attribute_method_matchers.each do |matcher| 263: unless instance_method_already_implemented?(matcher.method_name(attr_name)) 264: generate_method = "define_method_#{matcher.prefix}attribute#{matcher.suffix}" 265: 266: if respond_to?(generate_method) 267: send(generate_method, attr_name) 268: else 269: method_name = matcher.method_name(attr_name) 270: 271: 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__ + 1 272: end 273: end 274: end 275: end 276: @attribute_methods_generated = true 277: end
Removes all the previously dynamically defined methods from the class
# File lib/active_model/attribute_methods.rb, line 287 287: def undefine_attribute_methods 288: generated_attribute_methods.module_eval do 289: instance_methods.each { |m| undef_method(m) } 290: end 291: @attribute_methods_generated = nil 292: end
Disabled; run with --debug to generate this.
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