Module: Selections::BelongsToSelection

Defined in:
lib/selections/belongs_to_selection.rb

Instance Method Summary collapse

Instance Method Details

#belongs_to_selection(target, options = {}) ⇒ Object

Helper for belongs_to and accepts all the standard rails options

Example

class Thing < ActiveRecord::Base
  belongs_to_selection :priority

by default adds - class_name: “Selection”

This macro also adds a number of methods onto the class if there is a selection named as the class underscore name (eg: “thing_priority”), then methods are created for all of the selection values under that parent. For example:

thing = Thing.find(x)
thing.priority = Selection.thing_priority_high
thing.priority_high? #=> true
thing.priority_low?  #=> false

thing.priority_high? is equivalent to thing.priority == Selection.thing_priority_high except that the id of the selection is cached at the time the class is loaded.

Note that this is only appropriate to use for system selection values that are known at development time, and not to values that the users can edit in the live system.



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# File 'lib/selections/belongs_to_selection.rb', line 26

def belongs_to_selection(target, options={})
  belongs_to target, options.merge(:class_name => "Selection")

  # The "selections" table may not exist during certain rake scenarios such as db:migrate or db:reset.
  if ActiveRecord::Base.connection.table_exists? Selection.table_name
    prefix = self.name.downcase
    parent = Selection.where(system_code: "#{prefix}_#{target}").first
    if parent
      target_id = "#{target}_id".to_sym
      parent.children.each do |s|
        method_name = "#{s.system_code.sub("#{prefix}_", '')}?".to_sym
        class_eval do
          define_method method_name do
            send(target_id).to_i == s.id
          end
        end
      end
    end
  end
end