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# File activemodel/lib/active_model/attribute_methods.rb, line 238 def alias_attribute(new_name, old_name) attribute_method_matchers.each do |matcher| matcher_new = matcher.method_name(new_name).to_s matcher_old = matcher.method_name(old_name).to_s if matcher_new =~ COMPILABLE_REGEXP && matcher_old =~ COMPILABLE_REGEXP module_eval def #{matcher_new}(*args) send(:#{matcher_old}, *args) end, __FILE__, __LINE__ + 1 else define_method(matcher_new) do |*args| send(matcher_old, *args) end end 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'
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
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 activemodel/lib/active_model/attribute_methods.rb, line 100 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 # If we can compile the method name, do it. Otherwise use define_method. # This is an important *optimization*, please don't change it. define_method # has slower dispatch and consumes more memory. if name =~ COMPILABLE_REGEXP sing.class_eval def #{name}; #{value.nil? ? 'nil' : value.to_s.inspect}; end, __FILE__, __LINE__ + 1 else value = value.to_s if value sing.send(:define_method, name) { value } end end end
# File activemodel/lib/active_model/attribute_methods.rb, line 285 def define_attribute_method(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, __FILE__, __LINE__ + 1 if method_name.to_s =~ COMPILABLE_REGEXP generated_attribute_methods.module_eval def #{method_name}(*args) send(:#{matcher.method_missing_target}, '#{attr_name}', *args) end, __FILE__, __LINE__ + 1 else generated_attribute_methods.module_eval define_method('#{method_name}') do |*args| send('#{matcher.method_missing_target}', '#{attr_name}', *args) end, __FILE__, __LINE__ + 1 end end end end 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