r4854@ks: jeremy | 2006-07-30 00:59:18 -0700

 Attribute methods
 r4877@ks:  jeremy | 2006-07-30 20:23:53 -0700
 Factor the attribute#{suffix} methods out of method_missing for easier extension.
 r4878@ks:  jeremy | 2006-07-30 20:42:23 -0700
 More specific method naming, declare many attribute method suffixes, set up default suffixes at module include rather than lazily.


git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4632 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 75 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
new file mode 100644
index 0000000000..adc6eb6559
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -0,0 +1,75 @@
+module ActiveRecord
+  module AttributeMethods #:nodoc:
+    DEFAULT_SUFFIXES = %w(= ? _before_type_cast)
+
+    def self.included(base)
+      base.extend ClassMethods
+      base.attribute_method_suffix *DEFAULT_SUFFIXES
+    end
+
+    # Declare and check for suffixed attribute methods.
+    module ClassMethods
+      # Declare a method available for all attributes with the given suffix.
+      # Uses method_missing and respond_to? to rewrite the method
+      #   #{attr}#{suffix}(*args, &block)
+      # to
+      #   attribute#{suffix}(#{attr}, *args, &block)
+      #
+      # An attribute#{suffix} instance method must exist and accept at least
+      # the attr argument.
+      #
+      # For example:
+      #   class Person < ActiveRecord::Base
+      #     attribute_method_suffix '_changed?'
+      #
+      #     private
+      #       def attribute_changed?(attr)
+      #         ...
+      #       end
+      #   end
+      #
+      #   person = Person.find(1)
+      #   person.name_changed?    # => false
+      #   person.name = 'Hubert'
+      #   person.name_changed?    # => true
+      def attribute_method_suffix(*suffixes)
+        attribute_method_suffixes.concat suffixes
+        rebuild_attribute_method_regexp
+      end
+
+      # Returns MatchData if method_name is an attribute method.
+      def match_attribute_method?(method_name)
+        rebuild_attribute_method_regexp unless defined?(@@attribute_method_regexp) && @@attribute_method_regexp
+        @@attribute_method_regexp.match(method_name)
+      end
+
+      private
+        # Suffixes a, ?, c become regexp /(a|\?|c)$/
+        def rebuild_attribute_method_regexp
+          suffixes = attribute_method_suffixes.map { |s| Regexp.escape(s) }
+          @@attribute_method_regexp = /(#{suffixes.join('|')})$/.freeze
+        end
+
+        # Default to =, ?, _before_type_cast
+        def attribute_method_suffixes
+          @@attribute_method_suffixes ||= []
+        end
+    end
+
+    private
+      # Handle *? for method_missing.
+      def attribute?(attribute_name)
+        query_attribute(attribute_name)
+      end
+
+      # Handle *= for method_missing.
+      def attribute=(attribute_name, value)
+        write_attribute(attribute_name, value)
+      end
+
+      # Handle *_before_type_cast for method_missing.
+      def attribute_before_type_cast(attribute_name)
+        read_attribute_before_type_cast(attribute_name)
+      end
+  end
+end