Model Data Loading Patterns.md

Builder Pattern

Pros

• Familar
• Clean abstraction from model
• No model changes required

Cons

• Slow, 2N loading with cassandra-driver

Data Object Pattern

class Person
  attr_accessor :name

  def initialize(opts={})
    @name = opts[:name]
  end
end

Person.new(name: "eprothro")

or when loading from a hash

p = Person.new
p.name = row["name"]

becomes

class Person
  include DataState

  data_attr :name

end

Person.new(name: "eprothro")

or when loading from a hash

p = Person.new(TableAdapater.new(row))

Pros

• Fast, almost zero overhead added to cassandra-driver
• Easy serialization
• No public interface change
• Easy to raise if state unknown (from selection without attr)

Cons

• Not idiomatic
• More code, code relations twice (data model, model model)
• Complexity around contained non-primitives
• Requires change to modeling
• Theoretical muddiness with persisted-attributes concept in model