Module: ActiveModel::AttributeMethods::ClassMethods

### Home Classes Methods

### In Files

- lib/active_model/attribute_methods.rb

### Namespace

- CLASS ActiveModel::AttributeMethods::ClassMethods::AttributeMethodMatcher

### Methods

- #alias_attribute
- #attribute_method_affix
- #attribute_method_prefix
- #attribute_method_suffix
- #define_attribute_method
- #define_attribute_methods
- #instance_method_already_implemented?
- #undefine_attribute_methods

### Class/Module Index

Quicksearch

- ActiveModel
- ActiveModel::AttributeMethods
- ActiveModel::AttributeMethods::ClassMethods
- ActiveModel::AttributeMethods::ClassMethods::AttributeMethodMatcher
- ActiveModel::BlockValidator
- ActiveModel::Callbacks
- ActiveModel::Conversion
- ActiveModel::Dirty
- ActiveModel::EachValidator
- ActiveModel::Errors
- ActiveModel::Lint
- ActiveModel::Lint::Tests
- ActiveModel::MassAssignmentSecurity
- ActiveModel::MassAssignmentSecurity::BlackList
- ActiveModel::MassAssignmentSecurity::ClassMethods
- ActiveModel::MassAssignmentSecurity::Error
- ActiveModel::MassAssignmentSecurity::LoggerSanitizer
- ActiveModel::MassAssignmentSecurity::PermissionSet
- ActiveModel::MassAssignmentSecurity::Sanitizer
- ActiveModel::MassAssignmentSecurity::StrictSanitizer
- ActiveModel::MassAssignmentSecurity::WhiteList
- ActiveModel::MissingAttributeError
- ActiveModel::Name
- ActiveModel::Naming
- ActiveModel::Observer
- ActiveModel::ObserverArray
- ActiveModel::Observing
- ActiveModel::Observing::ClassMethods
- ActiveModel::SecurePassword
- ActiveModel::SecurePassword::ClassMethods
- ActiveModel::SecurePassword::InstanceMethodsOnActivation
- ActiveModel::Serialization
- ActiveModel::Serializers
- ActiveModel::Serializers::JSON
- ActiveModel::Serializers::Xml
- ActiveModel::StrictValidationFailed
- ActiveModel::Translation
- ActiveModel::Validations
- ActiveModel::Validations::AcceptanceValidator
- ActiveModel::Validations::Callbacks
- ActiveModel::Validations::Callbacks::ClassMethods
- ActiveModel::Validations::ClassMethods
- ActiveModel::Validations::ConfirmationValidator
- ActiveModel::Validations::ExclusionValidator
- ActiveModel::Validations::FormatValidator
- ActiveModel::Validations::HelperMethods
- ActiveModel::Validations::InclusionValidator
- ActiveModel::Validations::LengthValidator
- ActiveModel::Validations::NumericalityValidator
- ActiveModel::Validations::PresenceValidator
- ActiveModel::Validations::WithValidator
- ActiveModel::Validator

No matching classes.

# ActiveModel::AttributeMethods::ClassMethods

### Public Instance Methods

alias_attribute(new_name, old_name) click to toggle source

    # File lib/active_model/attribute_methods.rb, line 223
    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
        define_optimized_call self, matcher_new, matcher_old
      end
    end

attribute_method_affix(*affixes) click to toggle source

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 218
    def attribute_method_affix(*affixes)
      self.attribute_method_matchers += affixes.map { |affix| AttributeMethodMatcher.new :prefix => affix[:prefix], :suffix => affix[:suffix] }
      undefine_attribute_methods
    end

attribute_method_prefix(*prefixes) click to toggle source

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 143
    def attribute_method_prefix(*prefixes)
      self.attribute_method_matchers += prefixes.map { |prefix| AttributeMethodMatcher.new :prefix => prefix }
      undefine_attribute_methods
    end

attribute_method_suffix(*suffixes) click to toggle source

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 180
    def attribute_method_suffix(*suffixes)
      self.attribute_method_matchers += suffixes.map { |suffix| AttributeMethodMatcher.new :suffix => suffix }
      undefine_attribute_methods
    end

define_attribute_method(attr_name) click to toggle source

    # File lib/active_model/attribute_methods.rb, line 259
    def define_attribute_method(attr_name)
      attribute_method_matchers.each do |matcher|
        method_name = matcher.method_name(attr_name)

        unless instance_method_already_implemented?(method_name)
          generate_method = "define_method_#{matcher.method_missing_target}"

          if respond_to?(generate_method, true)
            send(generate_method, attr_name)
          else
            define_optimized_call generated_attribute_methods, method_name, matcher.method_missing_target, attr_name.to_s
          end
        end
      end
      attribute_method_matchers_cache.clear
    end

define_attribute_methods(attr_names) click to toggle source

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

    # File lib/active_model/attribute_methods.rb, line 255
    def define_attribute_methods(attr_names)
      attr_names.each { |attr_name| define_attribute_method(attr_name) }
    end

undefine_attribute_methods() click to toggle source

Removes all the previously dynamically defined methods from the class

    # File lib/active_model/attribute_methods.rb, line 277
    def undefine_attribute_methods
      generated_attribute_methods.module_eval do
        instance_methods.each { |m| undef_method(m) }
      end
      attribute_method_matchers_cache.clear
    end

### Protected Instance Methods

instance_method_already_implemented?(method_name) click to toggle source

    # File lib/active_model/attribute_methods.rb, line 294
    def instance_method_already_implemented?(method_name)
      generated_attribute_methods.method_defined?(method_name)
    end

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