020 RR Object Oriented Programming in Rails with Jim Weirich

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    • What is Object Oriented Programming?
    • If Ruby or Rails programmers aren't programming in an object oriented way does it matter?
    • The goal isn't to do OO for OO's sake.
    • Polymorphism
    • Tell, don't ask
    • Encapsulation
    • Case switching on the object's class can be refactored to take advantage of Polymorphism
    • Law of Demeter: Am I allowed to know this?
    • Single Responsibility Principle
    • Ask “What does this object do?” rather than building around the data contained in the object.
    • Presenters (The Presenter Pattern)
    • Steven Kabnik's Post on Object Oriented Programming and the Presenter Pattern in Rails
    • The problem with Helpers
    • In OO, you're allowed to add more Objects (or Classes)
    • Building your models without referencing ActiveRecord
    • Business objects that reference ActiveRecord data access objects
    • Object Thinking
    • The database is the last bastion of non-object oriented thinking
    • Behavior centric vs data centric design
    • The impedance mismatch between the database and the object oriented designs
    • Inheritance
    • Object Oriented Design centers around maintainability and complexity
    • Don't use generators
    • Create classes and evolve them into models as you need the persistence
    • Rather than asking for data, tell a class to do something for you
    • Three small things to watch out for:
      • Switch/case on class
      • Arrays and hashes or arrays of hashes of arrays (Primitive Obsession)
      • Subclassing Array or Hash
    • forwardable
    • delegate
    • Don't inherit from String
    • Enumerable module
    • Rake's FileList
    • Skinny Controllers
    • Is REST simply a way of pulling the impedance mismatch from the database all the way up to URL's?

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