Module: ActsAsLookupHasLookupClassMethods

Defined in:
lib/acts_as_lookup.rb

Instance Method Summary collapse

Instance Method Details

#force_class_load(cname) ⇒ Object

separate the logic for forcing a class load to isolate it, as well as making testing easier



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# File 'lib/acts_as_lookup.rb', line 245

def force_class_load(cname)
  # this is a hack that is not at all pretty but seems to get around the
  # double-class loading problems that arise in rails: see for example
  # https://rails.lighthouseapp.com/projects/8994/tickets/1339
  # it may create other problems though, so be careful....
  rails_root = nil
  begin
    rails_root = Rails.root
  rescue
  end
  # fallback for Rails 2
  rails_root ||= RAILS_ROOT if defined?(RAILS_ROOT)
  if !Object.const_defined?(cname)
    require File.join(rails_root, 'app', 'models', cname.underscore)
  end
end

#has_lookup(association_name, options = {}) ⇒ Object

create an association from the current rails model to a lookup model, providing a name for the association (default will assume the association name follows rails association naming conventions).

options:

:class_name: override the default assumption of class name from
             +assocaition_name+ argument and explicitly pass in the
             classname (in CamelCase) for the association.



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# File 'lib/acts_as_lookup.rb', line 217

def has_lookup(association_name, options = {})
  cname = options[:class_name] || association_name.to_s.camelize

  force_class_load cname

  # this is inspired/borrowed from Rapleaf's has_rap_enum
  klass = Kernel.const_get(cname)
  unless(klass && klass.is_a?(ActsAsLookupClassMethods))
    raise "#{cname.to_s.camelize} is not an acts_as_lookup class"
  end

  # create the reader method for the lookup association
  define_method(association_name) do
    klass.lookup_by_id(send("#{association_name}_id"))
  end

  # create the writer method for the lookup association
  define_method("#{association_name}=") do |assoc|
    unless (assoc.class.name == klass.name) || assoc.nil?
      raise "Argument not of type #{klass.name}"
    end
    send("#{association_name}_id=", assoc && assoc.id)
  end
end