ActiveRecord::Inheritance::ClassMethods
Methods
A
B
C
D
I
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S
Attributes
[RW] abstract_class

Set this to true if this is an abstract class (see abstract_class?). If you are using inheritance with ActiveRecord and don't want child classes to utilize the implied STI table name of the parent class, this will need to be true. For example, given the following:

class SuperClass < ActiveRecord::Base
  self.abstract_class = true
end
class Child < SuperClass
  self.table_name = 'the_table_i_really_want'
end

self.abstract_class = true is required to make Child<.find,.create, or any Arel method> use the_table_i_really_want instead of a table called super_classes
Instance Public methods
abstract_class?()

Returns whether this class is an abstract class or not.

Source: show | on GitHub 

# File activerecord/lib/active_record/inheritance.rb, line 125
def abstract_class?
  defined?(@abstract_class) && @abstract_class == true
end
base_class()

Returns the class descending directly from ActiveRecord::Base, or an abstract class, if any, in the inheritance hierarchy.

If A extends ActiveRecord::Base, A.base_class will return A. If B descends from A through some arbitrarily deep hierarchy, B.base_class will return A.

If B < A and C < B and if A is an #abstract_class then both B.base_class and C.base_class would return B as the answer since A is an abstract_class.

Source: show | on GitHub 

# File activerecord/lib/active_record/inheritance.rb, line 95
def base_class
  unless self < Base
    raise ActiveRecordError, "#{name} doesn't belong in a hierarchy descending from ActiveRecord"
  end

  if superclass == Base || superclass.abstract_class?
    self
  else
    superclass.base_class
  end
end
descends_from_active_record?()

Returns true if this does not need STI type condition. Returns false if STI type condition needs to be applied.

Source: show | on GitHub 

# File activerecord/lib/active_record/inheritance.rb, line 72
def descends_from_active_record?
  if self == Base
    false
  elsif superclass.abstract_class?
    superclass.descends_from_active_record?
  else
    superclass == Base || !columns_hash.include?(inheritance_column)
  end
end
inherited(subclass)

Source: show | on GitHub 

# File activerecord/lib/active_record/inheritance.rb, line 133
def inherited(subclass)
  subclass.instance_variable_set(:@_type_candidates_cache, Concurrent::Map.new)
  super
end
new(*args, &block)

Determines if one of the attributes passed in is the inheritance column, and if the inheritance column is attr accessible, it initializes an instance of the given subclass instead of the base class.

Source: show | on GitHub 

# File activerecord/lib/active_record/inheritance.rb, line 49
def new(*args, &block)
  if abstract_class? || self == Base
    raise NotImplementedError, "#{self} is an abstract class and cannot be instantiated."
  end

  attrs = args.first
  if has_attribute?(inheritance_column)
    subclass = subclass_from_attributes(attrs)

    if subclass.nil? && base_class == self
      subclass = subclass_from_attributes(column_defaults)
    end
  end

  if subclass && subclass != self
    subclass.new(*args, &block)
  else
    super
  end
end
sti_name()

Source: show | on GitHub 

# File activerecord/lib/active_record/inheritance.rb, line 129
def sti_name
  store_full_sti_class ? name : name.demodulize
end
Instance Protected methods
compute_type(type_name)

Returns the class type of the record using the current module as a prefix. So descendants of MyApp::Business::Account would appear as MyApp::Business::AccountSubclass.

Source: show | on GitHub 

# File activerecord/lib/active_record/inheritance.rb, line 142
def compute_type(type_name)
  if type_name.start_with?("::".freeze)
    # If the type is prefixed with a scope operator then we assume that
    # the type_name is an absolute reference.
    ActiveSupport::Dependencies.constantize(type_name)
  else
    type_candidate = @_type_candidates_cache[type_name]
    if type_candidate && type_constant = ActiveSupport::Dependencies.safe_constantize(type_candidate)
      return type_constant
    end

    # Build a list of candidates to search for
    candidates = []
    name.scan(/::|$/) { candidates.unshift "#{$`}::#{type_name}" }
    candidates << type_name

    candidates.each do |candidate|
      constant = ActiveSupport::Dependencies.safe_constantize(candidate)
      if candidate == constant.to_s
        @_type_candidates_cache[type_name] = candidate
        return constant
      end
    end

    raise NameError.new("uninitialized constant #{candidates.first}", candidates.first)
  end
end