DemeterMate

Introduction

DemeterMate is a Rails 3 plugin that gives your ActiveRecord models a way to access association methods without violating the Law of Demeter. For example, say a person has_many projects. If you'd like to find a person's project by id, you'd normally use

@person.projects.find id

This breaks the Law of Demeter, increasing coupling and making testing with stubs and mocks a chore. DemeterMate fixes this by making the following possible:

@person.find_project id

The following ActiveRecord methods are supported by DemeterMate:

:push
:concat
:build
:create
:create!
:size
:length
:count
:sum
:empty?
:clear
:delete
:delete_all
:destroy_all
:find
:find_first
:exists?
:uniq
:reset

So, if your Person model has_many Projects, you could add a new project like so:

@person.push_project project

DemeterMate is flexible with the order - both of the following are valid:

@person.projects_empty?
@person.empty_projects?

It's also flexible on inflection - use whichever makes sense:

@person.push_project project
@person.push_projects project

Usage

Person < ActiveRecord::Base
  has_many :projects
  demeter_mate :projects
end

Installation

rails plugin install git@github.com:skilldrick/demeter_mate.git

Copyright (c) 2011 Nick Morgan, released under the MIT license