vendor/gems/composite_primary_keys-1.1.0/lib/composite_primary_keys/attribute_methods.rb

   1 module CompositePrimaryKeys
   2   module ActiveRecord
   3     module AttributeMethods #:nodoc:
   4       def self.append_features(base)
   5         super
   6         base.send(:extend, ClassMethods)
   7       end
   8
   9       module ClassMethods
  10         # Define an attribute reader method.  Cope with nil column.
  11         def define_read_method(symbol, attr_name, column)
  12           cast_code = column.type_cast_code('v') if column
  13           cast_code = "::#{cast_code}" if cast_code && cast_code.match('ActiveRecord::.*')
  14           access_code = cast_code ? "(v=@attributes['#{attr_name}']) && #{cast_code}" : "@attributes['#{attr_name}']"
  15
  16           unless self.primary_keys.include?(attr_name.to_sym)
  17             access_code = access_code.insert(0, "missing_attribute('#{attr_name}', caller) unless @attributes.has_key?('#{attr_name}'); ")
  18           end
  19
  20           if cache_attribute?(attr_name)
  21             access_code = "@attributes_cache['#{attr_name}'] ||= (#{access_code})"
  22           end
  23
  24           evaluate_attribute_method attr_name, "def #{symbol}; #{access_code}; end"
  25         end
  26
  27         # Evaluate the definition for an attribute related method
  28         def evaluate_attribute_method(attr_name, method_definition, method_name=attr_name)
  29           unless primary_keys.include?(method_name.to_sym)
  30             generated_methods << method_name
  31           end
  32
  33           begin
  34             class_eval(method_definition, __FILE__, __LINE__)
  35           rescue SyntaxError => err
  36             generated_methods.delete(attr_name)
  37             if logger
  38               logger.warn "Exception occurred during reader method compilation."
  39               logger.warn "Maybe #{attr_name} is not a valid Ruby identifier?"
  40               logger.warn "#{err.message}"
  41             end
  42           end
  43         end
  44       end
  45
  46       # Allows access to the object attributes, which are held in the @attributes hash, as though they
  47       # were first-class methods. So a Person class with a name attribute can use Person#name and
  48       # Person#name= and never directly use the attributes hash -- except for multiple assigns with
  49       # ActiveRecord#attributes=. A Milestone class can also ask Milestone#completed? to test that
  50       # the completed attribute is not nil or 0.
  51       #
  52       # It's also possible to instantiate related objects, so a Client class belonging to the clients
  53       # table with a master_id foreign key can instantiate master through Client#master.
  54       def method_missing(method_id, *args, &block)
  55         method_name = method_id.to_s
  56
  57         # If we haven't generated any methods yet, generate them, then
  58         # see if we've created the method we're looking for.
  59         if !self.class.generated_methods?
  60           self.class.define_attribute_methods
  61
  62           if self.class.generated_methods.include?(method_name)
  63             return self.send(method_id, *args, &block)
  64           end
  65         end
  66
  67         if self.class.primary_keys.include?(method_name.to_sym)
  68           ids[self.class.primary_keys.index(method_name.to_sym)]
  69         elsif md = self.class.match_attribute_method?(method_name)
  70           attribute_name, method_type = md.pre_match, md.to_s
  71           if @attributes.include?(attribute_name)
  72             __send__("attribute#{method_type}", attribute_name, *args, &block)
  73           else
  74             super
  75           end
  76         elsif @attributes.include?(method_name)
  77           read_attribute(method_name)
  78         else
  79           super
  80         end
  81       end
  82     end
  83   end
  84 end