module BigRecord::ArReflection::ClassMethods

Reflection allows you to interrogate Big Record classes and objects about their associations and aggregations. This information can, for example, be used in a form builder that took an Active Record object and created input fields for all of the attributes depending on their type and displayed the associations to other objects.

You can find the interface for the AggregateReflection and AssociationReflection classes in the abstract MacroReflection class.

Public Instance Methods

create_reflection(macro, name, options, big_record) click to toggle source
# File lib/big_record/ar_reflection.rb, line 13
def create_reflection(macro, name, options, big_record)
  case macro
    when :has_many, :belongs_to, :has_one, :has_and_belongs_to_many
      reflection = ArAssociationReflection.new(macro, name, options, big_record)
    when :composed_of
      reflection = ArAggregateReflection.new(macro, name, options, big_record)
  end
  write_inheritable_hash :reflections, name => reflection
  reflection
end
reflect_on_aggregation(aggregation) click to toggle source

Returns the AggregateReflection object for the named aggregation (use the symbol). Example:

Account.reflect_on_aggregation(:balance) # returns the balance AggregateReflection
# File lib/big_record/ar_reflection.rb, line 43
def reflect_on_aggregation(aggregation)
  reflections[aggregation].is_a?(AggregateReflection) ? reflections[aggregation] : nil
end
reflect_on_all_aggregations() click to toggle source

Returns an array of AggregateReflection objects for all the aggregations in the class.

# File lib/big_record/ar_reflection.rb, line 35
def reflect_on_all_aggregations
  reflections.values.select { |reflection| reflection.is_a?(AggregateReflection) }
end
reflect_on_all_associations(macro = nil) click to toggle source

Returns an array of AssociationReflection objects for all the aggregations in the class. If you only want to reflect on a certain association type, pass in the symbol (:has_many, :has_one, :belongs_to) for that as the first parameter. Example:

Account.reflect_on_all_associations             # returns an array of all associations
Account.reflect_on_all_associations(:has_many)  # returns an array of all has_many associations
# File lib/big_record/ar_reflection.rb, line 54
def reflect_on_all_associations(macro = nil)
  association_reflections = reflections.values.select { |reflection| reflection.is_a?(AssociationReflection) }
  macro ? association_reflections.select { |reflection| reflection.macro == macro } : association_reflections
end
reflect_on_association(association) click to toggle source

Returns the AssociationReflection object for the named aggregation (use the symbol). Example:

Account.reflect_on_association(:owner) # returns the owner AssociationReflection
Invoice.reflect_on_association(:line_items).macro  # returns :has_many
# File lib/big_record/ar_reflection.rb, line 64
def reflect_on_association(association)
  reflections[association].is_a?(AssociationReflection) ? reflections[association] : nil
end
reflections() click to toggle source

Returns a hash containing all AssociationReflection objects for the current class Example:

Invoice.reflections
Account.reflections
# File lib/big_record/ar_reflection.rb, line 30
def reflections
  read_inheritable_attribute(:reflections) || write_inheritable_attribute(:reflections, {})
end