Module: Stannum::Entity

Includes:

Stannum::Entities::Attributes, Stannum::Entities::Constraints, Stannum::Entities::Properties

Defined in:

lib/stannum/entity.rb

Overview

Abstract module for defining objects with structured attributes.

Examples:

Defining Attributes

class Widget
  include Stannum::Entity

  attribute :name,        String
  attribute :description, String,  optional: true
  attribute :quantity,    Integer, default:  0
end

widget = Widget.new(name: 'Self-sealing Stem Bolt')
widget.name        #=> 'Self-sealing Stem Bolt'
widget.description #=> nil
widget.quantity    #=> 0
widget.attributes  #=>
# {
#   name:        'Self-sealing Stem Bolt',
#   description: nil,
#   quantity:    0
# }

Setting Attributes

widget.description = 'A stem bolt, but self sealing.'
widget.attributes #=>
# {
#   name:        'Self-sealing Stem Bolt',
#   description: 'A stem bolt, but self sealing.',
#   quantity:    0
# }

widget.assign_attributes(quantity: 50)
widget.attributes #=>
# {
#   name:        'Self-sealing Stem Bolt',
#   description: 'A stem bolt, but self sealing.',
#   quantity:    50
# }

widget.attributes = (name: 'Inverse Chronoton Emitter')
# {
#   name:        'Inverse Chronoton Emitter',
#   description: nil,
#   quantity:    0
# }

Defining Attribute Constraints

Widget::Contract.matches?(quantity: -5)                    #=> false
Widget::Contract.matches?(name: 'Capacitor', quantity: -5) #=> true

class Widget
  constraint(:quantity) { |qty| qty >= 0 }
end

Widget::Contract.matches?(name: 'Capacitor', quantity: -5) #=> false
Widget::Contract.matches?(name: 'Capacitor', quantity: 10) #=> true

Defining Struct Constraints

Widget::Contract.matches?(name: 'Diode') #=> true

class Widget
  constraint { |struct| struct.description&.include?(struct.name) }
end

Widget::Contract.matches?(name: 'Diode') #=> false
Widget::Contract.matches?(
  name:        'Diode',
  description: 'A low budget Diode',
) #=> true

Method Summary

Methods included from Stannum::Entities::Constraints

apply

Methods included from Stannum::Entities::Attributes

apply, #assign_attributes, #attributes, #attributes=, #initialize, #properties

Methods included from Stannum::Entities::Properties

#==, #[], #[]=, #assign_properties, #initialize, #inspect, #properties, #properties=, #to_h