Module: HasAssociativeFacades::InstanceMethods

Defined in:
lib/has_associative_facades/instance_methods.rb

Instance Method Summary collapse

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args) ⇒ Object

When the method being called is the case of “#association_name_#attribute_or_method” a getter method will be defined and called returning its value. This works for an ActiveRecord object created through the new operator having all attributes set to nil or an find of some sort having all attributes populated.

If the associated object is nil but has an attribute or method with the given name a nil is reurned. Otherwise, the NoMethodError is raised.



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# File 'lib/has_associative_facades/instance_methods.rb', line 11

def method_missing( method, *args )
  method_name = method.to_s
  super( method, *args ) # allow super to win if it has the method
rescue NoMethodError => ex
  association = nil
  association_reflection = nil
  associateds = self.class.inheritable_attributes[:reflections]
  associateds.each do |associated|
    if /#{associated[0]}_/.match( method_name )
      association_reflection = associated
      association = associated[0]
      break
    end
  end
  if association.nil?
    raise NoMethodError.new('has_associative_facades could find no ' +
                            'association to resolve ' +
                            "#{self.class.name}##{method}",
                            method,
                            args)
  end

  if match = /#{association}_([_a-zA-Z]\w*)/.match( method_name )
    if match.captures.empty? || match.captures.size > 2
      raise NoMethodError.new('has_associative_facades failed to resolve ' +
                              "#{self.class.name}##{method} via "          +
                              "#{self.class.name}##{association}",
                              method,
                              args)
    end
    attribute = match.captures[0].to_sym

    assoc_klass = nil
    begin
      assoc_klass = association.to_s.classify.constantize
    rescue
      assoc_klass = association_reflection[1].options[:class_name].constantize
    end
    unless assoc_klass.columns_hash.has_key?( attribute.to_s ) || assoc_klass.public_instance_methods.include?( attribute.to_s )
      if match.captures.empty? || match.captures.size > 2
        raise NoMethodError.new('has_associative_facades could find no ' +
                                "#{assoc_klass.name}##{method} "         +
                                'method to resolve '                     +
                                "#{self.class.name}##{method}",
                                method,
                                args)
      end
    end

    self.class.class_eval <<-END
    def #{method_name}
      return self.send( :#{association} ).send( :#{attribute} ) unless self.send( :#{association} ).nil?
      nil
    end
    END

    return self.send( method_name )
  end

  raise NoMethodError.new('has_associative_facades failed to resolve ' +
                          "#{self.class.name}##{method} via "          +
                          "any association on #{self.class.name}",
                          method,
                          args)
end