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-rw-r--r--activerecord/lib/active_record/aggregations.rb20
1 files changed, 10 insertions, 10 deletions
diff --git a/activerecord/lib/active_record/aggregations.rb b/activerecord/lib/active_record/aggregations.rb
index c7a329d74d..3ae7030caa 100644
--- a/activerecord/lib/active_record/aggregations.rb
+++ b/activerecord/lib/active_record/aggregations.rb
@@ -10,9 +10,9 @@ module ActiveRecord
# Active Record implements aggregation through a macro-like class method called +composed_of+
# for representing attributes as value objects. It expresses relationships like "Account [is]
# composed of Money [among other things]" or "Person [is] composed of [an] address". Each call
- # to the macro adds a description of how the value objects are created from the attributes of
- # the entity object (when the entity is initialized either as a new object or from finding an
- # existing object) and how it can be turned back into attributes (when the entity is saved to
+ # to the macro adds a description of how the value objects are created from the attributes of
+ # the entity object (when the entity is initialized either as a new object or from finding an
+ # existing object) and how it can be turned back into attributes (when the entity is saved to
# the database).
#
# class Customer < ActiveRecord::Base
@@ -193,7 +193,8 @@ module ActiveRecord
# * <tt>:converter</tt> - A symbol specifying the name of a class method of <tt>:class_name</tt>
# or a Proc that is called when a new value is assigned to the value object. The converter is
# passed the single value that is used in the assignment and is only called if the new value is
- # not an instance of <tt>:class_name</tt>.
+ # not an instance of <tt>:class_name</tt>. If <tt>:allow_nil</tt> is set to true, the converter
+ # can return nil to skip the assignment.
#
# Option examples:
# composed_of :temperature, :mapping => %w(reading celsius)
@@ -241,16 +242,15 @@ module ActiveRecord
def writer_method(name, class_name, mapping, allow_nil, converter)
define_method("#{name}=") do |part|
+ klass = class_name.constantize
+ unless part.is_a?(klass) || converter.nil? || part.nil?
+ part = converter.respond_to?(:call) ? converter.call(part) : klass.send(converter, part)
+ end
+
if part.nil? && allow_nil
mapping.each { |pair| self[pair.first] = nil }
@aggregation_cache[name] = nil
else
- unless part.is_a?(class_name.constantize) || converter.nil?
- part = converter.respond_to?(:call) ?
- converter.call(part) :
- class_name.constantize.send(converter, part)
- end
-
mapping.each { |pair| self[pair.first] = part.send(pair.last) }
@aggregation_cache[name] = part.freeze
end