ActiveModel: Make Any Ruby Object Feel Like ActiveRecord

http://yehudakatz.com/2010/01/10/activemodel-make-any-ruby-object-feel-like-activerecord/

• ActiveModel API

the important thing about the ActiveModel API is that your models can become ActiveModel compliant without using a single line of Rails code

use "include ActiveModel::Lint::Tests” to make sure your model become ActiveModel compliant

• The Validations System

use "include ActiveModel::Validations” to add validation module to your model

The validations system calls read_attribute_for_validation to get the attribute, but by default, it aliases that method to send, which supports the standard Ruby attribute system of attr accessor

validates_presence_of is using the more primitive validates_with, passing it the validator class, merging in {:attributes => attribute names} into the options passed to the validator

• Serialization

include ActiveModel::Serialization

ActiveRecord also comes with default serialization for JSON and XML

• AttributeMethods: Makes it easy to add attributes that are set like table_name :foo
• Callbacks: ActiveRecord-style lifecycle callbacks.
• Dirty: Support for dirty tracking
• Naming: Default implementations of model.model_name, which are used by ActionPack (for instance, when you do render :partial => model
• Observing: ActiveRecord-style observers
• StateMachine: A simple state-machine implementation for models
• Translation: The core translation support