diff options
Diffstat (limited to 'activemodel')
| -rw-r--r-- | activemodel/README | 25 | ||||
| -rw-r--r-- | activemodel/lib/active_model/attribute_methods.rb | 141 |
2 files changed, 143 insertions, 23 deletions
diff --git a/activemodel/README b/activemodel/README index cc687e51ed..c8814a9ea3 100644 --- a/activemodel/README +++ b/activemodel/README @@ -12,9 +12,30 @@ Active Model provides a known set of interfaces that your objects can implement to then present a common interface to the Action Pack helpers. You can include functionality from the following modules: +* Adding attribute magic to your objects + + Add prefixes and suffixes to defined attribute methods... + + class Person + include ActiveModel::AttributeMethods + + attribute_method_prefix 'clear_' + define_attribute_methods [:name, :age] + + attr_accessor :name, :age + + def clear_attribute(attr) + send("#{attr}=", nil) + end + end + + ...gives you clear_name, clear_age. + + {Learn more}[link:classes/ActiveModel/AttributeMethods.html] + * Adding callbacks to your objects - class MyClass + class Person extend ActiveModel::Callbacks define_model_callbacks :create @@ -32,7 +53,7 @@ functionality from the following modules: * For classes that already look like an Active Record object - class MyClass + class Person include ActiveModel::Conversion end diff --git a/activemodel/lib/active_model/attribute_methods.rb b/activemodel/lib/active_model/attribute_methods.rb index 977a101277..32ddf1d579 100644 --- a/activemodel/lib/active_model/attribute_methods.rb +++ b/activemodel/lib/active_model/attribute_methods.rb @@ -5,10 +5,51 @@ module ActiveModel class MissingAttributeError < NoMethodError end + # <tt>ActiveModel::AttributeMethods</tt> provides a way to add prefixes and suffixes + # to your methods as well as handling the creation of Active Record like class methods + # such as +table_name+. + # + # The requirements to implement ActiveModel::AttributeMethods are: + # + # * <tt>include ActiveModel::AttributeMethods</tt> in your object + # * Call each Attribute Method module method you want to add, such as + # attribute_method_suffix or attribute_method_prefix + # * Call <tt>define_attribute_methods</tt> after the other methods are + # called. + # * Define the various generic +_attribute+ methods that you have declared + # + # A minimal implementation could be: + # + # class Person + # + # include ActiveModel::AttributeMethods + # + # attribute_method_affix :prefix => 'reset_', :suffix => '_to_default!' + # attribute_method_suffix '_contrived?' + # attribute_method_prefix 'clear_' + # define_attribute_methods ['name'] + # + # attr_accessor :name + # + # private + # + # def attribute_contrived?(attr) + # true + # end + # + # def clear_attribute(attr) + # send("#{attr}=", nil) + # end + # + # def reset_attribute_to_default!(attr) + # send("#{attr}=", "Default Name") + # end + # + # end + # module AttributeMethods extend ActiveSupport::Concern - # Declare and check for suffixed attribute methods. module ClassMethods # Defines an "attribute" method (like +inheritance_column+ or # +table_name+). A new (class) method will be created with the @@ -22,12 +63,27 @@ module ActiveModel # # Example: # - # class A < ActiveRecord::Base + # 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 + # + # Provivdes you with: + # + # AttributePerson.primary_key + # # => "sysid" + # AttributePerson.inheritance_column = 'address' + # AttributePerson.inheritance_column + # # => 'address_id' def define_attr_method(name, value=nil, &block) sing = metaclass sing.send :alias_method, "original_#{name}", name @@ -54,19 +110,25 @@ module ActiveModel # # For example: # - # class Person < ActiveRecord::Base + # class Person + # + # include ActiveModel::AttributeMethods + # attr_accessor :name # attribute_method_prefix 'clear_' + # define_attribute_methods [:name] # # private - # def clear_attribute(attr) - # ... - # end + # + # def clear_attribute(attr) + # send("#{attr}=", nil) + # end # end # - # person = Person.find(1) - # person.name # => 'Gem' + # person = Person.new + # person.name = "Bob" + # person.name # => "Bob" # person.clear_name - # person.name # => '' + # person.name # => nil def attribute_method_prefix(*prefixes) attribute_method_matchers.concat(prefixes.map { |prefix| AttributeMethodMatcher.new :prefix => prefix }) undefine_attribute_methods @@ -86,18 +148,24 @@ module ActiveModel # # For example: # - # class Person < ActiveRecord::Base + # class Person + # + # include ActiveModel::AttributeMethods + # attr_accessor :name # attribute_method_suffix '_short?' + # define_attribute_methods [:name] # # private - # def attribute_short?(attr) - # ... - # end + # + # def attribute_short?(attr) + # send(attr).length < 5 + # end # end # - # person = Person.find(1) - # person.name # => 'Gem' - # person.name_short? # => true + # person = Person.new + # person.name = "Bob" + # person.name # => "Bob" + # person.name_short? # => true def attribute_method_suffix(*suffixes) attribute_method_matchers.concat(suffixes.map { |suffix| AttributeMethodMatcher.new :suffix => suffix }) undefine_attribute_methods @@ -118,16 +186,21 @@ module ActiveModel # # For example: # - # class Person < ActiveRecord::Base + # 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 + # + # def reset_attribute_to_default!(attr) + # ... + # end # end # - # person = Person.find(1) + # person = Person.new # person.name # => 'Gem' # person.reset_name_to_default! # person.name # => 'Gemma' @@ -146,6 +219,30 @@ module ActiveModel 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 def define_attribute_methods(attr_names) return if attribute_methods_generated? attr_names.each do |attr_name| @@ -168,6 +265,7 @@ module ActiveModel @attribute_methods_generated = true end + # Removes all the preiously dynamically defined methods from the class def undefine_attribute_methods generated_attribute_methods.module_eval do instance_methods.each { |m| undef_method(m) } @@ -183,6 +281,7 @@ module ActiveModel end end + # Returns true if the attribute methods defined have been generated. def attribute_methods_generated? @attribute_methods_generated ||= nil end |