Module: SelectiveAttributeProxy

Included in:
Aliyun::ESS::Collection, Aliyun::ESS::ScalingGroup, Aliyun::ESS::ScalingInstance, Aliyun::ESS::ScalingRule
Defined in:
lib/aliyun/ess/extensions.rb

Defined Under Namespace

Modules: ClassMethods

Class Method Summary collapse

Class Method Details

.included(klass) ⇒ Object 



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# File 'lib/aliyun/ess/extensions.rb', line 113

def self.included(klass)
  klass.extend(ClassMethods)
  klass.class_eval(<<-EVAL, __FILE__, __LINE__)
    cattr_accessor :attribute_proxy
    cattr_accessor :attribute_proxy_options
    
    # Default name for attribute storage
    self.attribute_proxy         = :attributes
    self.attribute_proxy_options = {:exclusively => true}
    
    private
      # By default proxy all attributes
      def proxiable_attribute?(name)
        return true unless self.class.attribute_proxy_options[:exclusively]
        send(self.class.attribute_proxy).has_key?(name)
      end
      
      def method_missing(method, *args, &block)
        # Autovivify attribute storage
        if method == self.class.attribute_proxy
          ivar = "@\#{method}"
          instance_variable_set(ivar, {}) unless instance_variable_get(ivar).is_a?(Hash)
          instance_variable_get(ivar)
        # Delegate to attribute storage
        elsif method.to_s =~ /^(\\w+)(=?)$/ && proxiable_attribute?($1)
          attributes_hash_name = self.class.attribute_proxy
          $2.empty? ? send(attributes_hash_name)[$1] : send(attributes_hash_name)[$1] = args.first
        else
          super
        end
      end
  EVAL
end