Class: Object

Inherits:
BasicObject
Defined in:
lib/acts_as_interface.rb

Overview

Include ActsAsInterface to easily define abstract methods Example: Superclass class Person

abstract_methods :dance, :eat
abstract_methods :sleep, :play, :visibility => :private
callbacks :prance

abstract_methods :foo, :for => :class
callbacks :france, :for => :class, :visibility => :protected

end

me = MyClass.new me.dance #raises NotImplementedError me.play #raises NoMethodError: private method ‘close_book` called me.send(:play) #calls empty method play me.prance #calls empty method prance Person.foo #raises NotImplementedError

Example: ActiveRecord Module module ActsAsPerson

# included in active record objects where abstracted methods can be either attributes of the model or defined by the model
def self.included(base)
  base.instance_eval do
    include ActsAsInterface
    abstract_methods :name, :dance
  end
end

end

Instance Method Summary collapse

Instance Method Details

#define_abstract_method(abstract_method_name, options) ⇒ Object 



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# File 'lib/acts_as_interface.rb', line 34

def define_abstract_method(abstract_method_name, options)
  model_columns = []
  error_on_column_load = false
  begin
    model_columns = respond_to?(:columns) ? columns : []
  rescue
    error_on_column_load = true
  end

  unless method_defined?(abstract_method_name) or error_on_column_load or model_columns.any? { |column| column.name.to_sym == abstract_method_name }
    define_method(abstract_method_name) do |*abstract_method_args|
      if options.has_key?(:default)
        options[:default]
      else 
        class_name = options[:for] == :class ? self : self.class
        raise NotImplementedError, "#{abstract_method_name} not defined for #{class_name}"
      end      
    end
  
    send(options[:visibility], abstract_method_name) if options[:visibility]
  end
end