Module: ActiveModel::AttributeMethods::ClassMethods

Defined in:
activemodel/lib/active_model/attribute_methods.rb

Defined Under Namespace

Classes: AttributeMethodMatcher

Instance Method Summary collapse

Instance Method Details

#alias_attribute(new_name, old_name) ⇒ Object


223
224
225
226
227
228
229
# File 'activemodel/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) ⇒ Object

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'

218
219
220
221
# File 'activemodel/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) ⇒ Object

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

143
144
145
146
# File 'activemodel/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) ⇒ Object

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

180
181
182
183
# File 'activemodel/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_attr_method(name, value = nil, deprecation_warning = true, &block) ⇒ Object

:nodoc:


69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
# File 'activemodel/lib/active_model/attribute_methods.rb', line 69

def define_attr_method(name, value=nil, deprecation_warning = true, &block) #:nodoc:
  # This deprecation_warning param is for internal use so that we can silence
  # the warning from Active Record, because we are implementing more specific
  # messages there instead.
  #
  # It doesn't apply to the original_#{name} method as we want to warn if
  # people are calling that regardless.
  if deprecation_warning
    ActiveSupport::Deprecation.warn("define_attr_method is deprecated and will be removed without replacement.")
  end

  sing = singleton_class
  sing.class_eval <<-eorb, __FILE__, __LINE__ + 1
    remove_possible_method :'original_#{name}'
    remove_possible_method :'_original_#{name}'
    alias_method :'_original_#{name}', :'#{name}'
    define_method :'original_#{name}' do
      ActiveSupport::Deprecation.warn(
        "This method is generated by ActiveModel::AttributeMethods::ClassMethods#define_attr_method, " \
        "which is deprecated and will be removed."
      )
      send(:'_original_#{name}')
    end
  eorb
  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 =~ NAME_COMPILABLE_REGEXP
      sing.class_eval <<-RUBY, __FILE__, __LINE__ + 1
        def #{name}; #{value.nil? ? 'nil' : value.to_s.inspect}; end
      RUBY
    else
      value = value.to_s if value
      sing.send(:define_method, name) { value }
    end
  end
end

#define_attribute_method(attr_name) ⇒ Object


259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
# File 'activemodel/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) ⇒ Object

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

255
256
257
# File 'activemodel/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

#generated_attribute_methodsObject

Returns true if the attribute methods defined have been generated.


285
286
287
288
289
290
291
# File 'activemodel/lib/active_model/attribute_methods.rb', line 285

def generated_attribute_methods #:nodoc:
  @generated_attribute_methods ||= begin
    mod = Module.new
    include mod
    mod
  end
end

#undefine_attribute_methodsObject

Removes all the previously dynamically defined methods from the class


277
278
279
280
281
282
# File 'activemodel/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