Pad

A gem that enables a Ports and Adapter architectural style with Domain Driven Design.

Installation

Add this line to your application's Gemfile:

gem 'pad'

And then execute:

$ bundle

Or install it yourself as:

$ gem install pad

Usage

Models

You can create your own models and use Pad attributes by including Pad.model in your classes. This will add an attribute method you can use to add attributes to your class.

require 'pad'

class Vehicle
  include Pad.model

  attribute :year
  attribute :manufacturer
  attribute :make
end

Attribute values can be passed into the constructor as a hash using a key of the attribute name.

sienna = Vehicle.new year: 2006, manufacturer: 'Toyota', make: 'Sienna' # => #<Vehicle:0x007fcdacd2ff38 @year=2006, @manufacturer="Toyota", @make="Sienna">

And readers and writers are available for each attribute:

sienna.year # => 2006
sienna.year = 2007
sienna  # => #<Vehicle:0x007fcdacd2ff38 @year=2007, @manufacturer="Toyota", @make="Sienna">

You can set the type of an attribute

  attribute :name, String

You can set the visibility of attributes:

  attribute :private,   String, reader: :private,   writer: :private
  attribute :protected, String, reader: :protected, writer: :protected
  attribute :public,    String, reader: :public,    writer: :public

Entities

You can create entities which extend models with a built-in 'id' attribute which uniquely identifies the entity.

require 'pad'

class Person
  include Pad.entity

  attribute :name
  attribute :age
end

dave = Person.new id: 21, name: "Dave", age: 32 # => #<Person:0x007feaf4a3c668 @id=21, @name="Dave", @age=32>
dave.id   # => 21
dave.name # => "Dave"
dave.age  # => 32

another_dave = Person.new id: 21
dave == another_dave # => true

Value Objects

You can create value objects which have use read-only attribute values to denote equality. Attribute values are passed into the constructor as a hash. Attributes to be considered when checking equality are surrounded by a values block.

require 'pad'

class Price
  include Pad.value_object

  values do
    attribute :cost
    attribute :currency
  end

  attribute :id
end

pen1 = Price.new id: 1, cost: 100, currency: 'CAD' # => ##<Price cost=100 currency="CAD">
pen2 = Price.new id: 2, cost: 100, currency: 'CAD' # => ##<Price cost=100 currency="CAD">
pen3 = Price.new id: 3, cost: 999, currency: 'CAD' # => ##<Price cost=100 currency="CAD">

pen1 == pen2 # => true
pen1 == pen3 # => false

Contributing

1. Fork it ( https://github.com/dwhelan/pad/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request