oop-interface - OOP interfaces for Ruby

The main idea behind of implementation of such gem, was limiting the scope. For example when you are implementing Aggregate Root (following Domain Driven Design) in ActiveRecord, you would like to expose only public contract methods to ensure that Aggregate Root boundaries are not crossed by using directly relations or ActiveRecord methods.

This gem takes inspiration from https://github.com/shuber/interface and borrow some implementation details from it, extend it and modify available api.

Credits for Sean Huber

Installation

Add this line to your application's Gemfile:

gem 'oop-interface'

And then execute:

$ bundle

Or install it yourself as:

$ gem install oop-interface

Usage

Example usage:

  require "interface"

  module Order
    def submit; end
    def add_position(_position); end
  end

  module Saver
    def save; end
  end

  class OrderImpl
    include Interface
    implements Order, Saver
    def submit
      :submitted
    end

    def save(some: 5)
      "save #{some}"
    end
  end
  
  > OrderImpl.interfaces
  => [Order, Saver] 
   
  > OrderImpl.unimplemented_methods
  => {Order=>[:add_position]} 
   
  > saver = OrderImpl.new.as(Saver)
  => #<Saver:70247745038560> 
   
  > saver.submit
  NoMethodError: undefined method `submit' for #<Saver:70247745038560>
  
  > saver.save(some: 8)
  => "save 8"
  
  > OrderImpl.new.add_position
  NotImplementedError: OrderImpl needs to implement 'add_position' for interface Order
  
  > OrderImpl.new.is_a? Saver
  => true 
  
  > OrderImpl.new.is_a? Order
  => true
  
  # In DDD
  
  class OrderImpl < ApplicationRecord
    include Interface
    implements Order
    
    has_many :order_lines, ...
    
    def submit
      :submitted
    end
  end
  
  class OrderRepository
    def load(aggregate_id)
      OrderImpl.find(aggregate_id).as(Order)
    end
  end
  
  > order = OrderRepository.new.load(aggregate_id)
  => #<Order:70247745038560>
  
  > order.save
  NoMethodError: undefined method `save' for #<Order:70247745038560>
  
  > order.order_lines 
  NoMethodError: undefined method `order_lines' for #<Order:70247745038560>
  
  > order.submit
  => :submittted

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/andrzejsliwa/oop-interface.

License