Class: Virtus::Attributes::Attribute

Inherits:
Object
  • Object
show all
Defined in:
lib/virtus/attributes/attribute.rb

Direct Known Subclasses

Object

Constant Summary collapse

OPTIONS = 
[ :primitive, :complex, :accessor, :reader, :writer ].freeze
DEFAULT_ACCESSOR = 
:public.freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, model, options = {}) ⇒ Attribute

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Initializes an attribute instance

Parameters:

  • name (Symbol) —

    the name of an attribute

  • model (Class) —

    the object’s class

  • options (Hash) (defaults to: {}) —

    hash of extra options which overrides defaults set on an attribute class



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# File 'lib/virtus/attributes/attribute.rb', line 105

def initialize(name, model, options = {})
  @name    = name
  @model   = model
  @options = self.class.options.merge(options).freeze

  @instance_variable_name = "@#{@name}".freeze

  default_accessor   = @options.fetch(:accessor, DEFAULT_ACCESSOR)
  @reader_visibility = @options.fetch(:reader, default_accessor)
  @writer_visibility = @options.fetch(:writer, default_accessor)

  _create_reader
  _create_writer
end

Instance Attribute Details

#instance_variable_name ⇒ Object (readonly)

Returns the value of attribute instance_variable_name.



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# File 'lib/virtus/attributes/attribute.rb', line 4

def instance_variable_name
  @instance_variable_name
end

#model ⇒ Object (readonly)

Returns the value of attribute model.



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# File 'lib/virtus/attributes/attribute.rb', line 4

def model
  @model
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/virtus/attributes/attribute.rb', line 4

def name
  @name
end

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/virtus/attributes/attribute.rb', line 4

def options
  @options
end

#reader_visibility ⇒ Object (readonly)

Returns the value of attribute reader_visibility.



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# File 'lib/virtus/attributes/attribute.rb', line 4

def reader_visibility
  @reader_visibility
end

#writer_visibility ⇒ Object (readonly)

Returns the value of attribute writer_visibility.



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# File 'lib/virtus/attributes/attribute.rb', line 4

def writer_visibility
  @writer_visibility
end

Class Method Details

.accept_options(*args) ⇒ Object

Defines which options are valid for a given attribute class.

Example:

class MyAttribute < Virtus::Attributes::Object
  accept_options :foo, :bar
end



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# File 'lib/virtus/attributes/attribute.rb', line 31

def accept_options(*args)
  accepted_options.concat(args)

  # create methods for each new option
  args.each do |attribute_option|
    class_eval <<-RUBY, __FILE__, __LINE__ + 1
    def self.#{attribute_option}(value = Undefined)          # def self.unique(value = Undefined)
      return @#{attribute_option} if value.equal?(Undefined) #   return @unique if value.equal?(Undefined)
      @#{attribute_option} = value                           #   @unique = value
    end                                                      # end
    RUBY
  end

  descendants.each { |descendant| descendant.accepted_options.concat(args) }
end

.accepted_options ⇒ Array

Returns an array of valid options

Returns:

  • (Array) —

    the array of valid option names



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# File 'lib/virtus/attributes/attribute.rb', line 18

def accepted_options
  @accepted_options ||= []
end

.descendants ⇒ Array

Returns all the descendant classes

Returns:

  • (Array) —

    the array of descendants



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# File 'lib/virtus/attributes/attribute.rb', line 53

def descendants
  @descendants ||= []
end

.inherited(descendant) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Adds descendant to descendants array and inherits default options



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# File 'lib/virtus/attributes/attribute.rb', line 75

def inherited(descendant)
  descendants << descendant
  descendant.accepted_options.concat(accepted_options)
  options.each { |key, value| descendant.send(key, value) }
end

.options ⇒ Hash

Returns default options hash for a give attribute class.

Returns:

  • (Hash) —

    a hash of default option values



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# File 'lib/virtus/attributes/attribute.rb', line 63

def options
  options = {}
  accepted_options.each do |method|
    value = send(method)
    options[method] = value unless value.nil?
  end
  options
end

Instance Method Details

#_create_reader ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Creates an attribute reader method



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# File 'lib/virtus/attributes/attribute.rb', line 183

def _create_reader
  model.class_eval <<-RUBY, __FILE__, __LINE__ + 1
    chainable(:attribute) do
      #{reader_visibility}

      def #{name}
        return #{instance_variable_name} if defined?(#{instance_variable_name})
        attribute = self.class.attributes[#{name.inspect}]
      #{instance_variable_name} = attribute ? attribute.get(self) : nil
      end
    end
  RUBY

end

#_create_writer ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Creates an attribute writer method



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# File 'lib/virtus/attributes/attribute.rb', line 201

def _create_writer
  model.class_eval <<-RUBY, __FILE__, __LINE__ + 1
    chainable(:attribute) do
      #{writer_visibility}

      def #{name}=(value)
        self.class.attributes[#{name.inspect}].set(self, value)
      end
    end
  RUBY
end

#complex? ⇒ TrueClass, FalseClass

Returns if an attribute is a complex one.

Returns:

  • (TrueClass, FalseClass) 


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# File 'lib/virtus/attributes/attribute.rb', line 89

def complex?
  options[:complex]
end

#get(model) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns value of an attribute for the given model



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# File 'lib/virtus/attributes/attribute.rb', line 154

def get(model)
  get!(model)
end

#get!(model) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns the instance variable of the attribute



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# File 'lib/virtus/attributes/attribute.rb', line 161

def get!(model)
  model.instance_variable_get(instance_variable_name)
end

#primitive?(value) ⇒ TrueClass, FalseClass

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns if the given value’s class is an attribute’s primitive

Returns:

  • (TrueClass, FalseClass) 


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# File 'lib/virtus/attributes/attribute.rb', line 125

def primitive?(value)
  value.kind_of?(self.class.primitive)
end

#set(model, value) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Sets the value on the model



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# File 'lib/virtus/attributes/attribute.rb', line 168

def set(model, value)
  return if value.nil?
  set!(model, typecast(value, model))
end

#set!(model, value) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Sets instance variable of the attribute



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# File 'lib/virtus/attributes/attribute.rb', line 176

def set!(model, value)
  model.instance_variable_set(instance_variable_name, value)
end

#typecast(value, model = nil) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Converts the given value to the primitive type unless it’s already the primitive or nil

Parameters:

  • value (Object) —

    the value



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# File 'lib/virtus/attributes/attribute.rb', line 136

def typecast(value, model = nil)
  if value.nil? || primitive?(value)
    value
  else
    typecast_to_primitive(value)
  end
end

#typecast_to_primitive(value, model) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Converts the given value to the primitive type



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# File 'lib/virtus/attributes/attribute.rb', line 147

def typecast_to_primitive(value, model)
  value
end