From 67c390ae4cfed8dc7923fcab0980302af1f8aeea Mon Sep 17 00:00:00 2001
From: Vijay Aravamudhan <avijayr - at - gmail - dot - com>
Date: Sun, 5 Apr 2009 14:37:07 -0500
Subject: [PATCH] Added utility method that can be used while serializing (for eg in to_xml) to denote whether any associated objects exist at that time.

---
 activerecord/lib/active_record/reflection.rb |    8 +++++++
 activerecord/test/cases/reflection_test.rb   |   28 ++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index 2d4c1d5..c4c4278 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -140,6 +140,14 @@ module ActiveRecord
 
     # Holds all the meta-data about an association as it was specified in the Active Record class.
     class AssociationReflection < MacroReflection #:nodoc:
+      def initialize(macro, name, options, active_record)
+        super(macro, name, options, active_record)
+        if active_record && name
+          active_record.send(:define_method, "has_#{name}?") { !self.send(name).blank? }
+          active_record.send(:alias_method, "has_#{name}", "has_#{name}?")
+        end
+      end
+
       # Returns the target association's class:
       #
       #   class Author < ActiveRecord::Base
diff --git a/activerecord/test/cases/reflection_test.rb b/activerecord/test/cases/reflection_test.rb
index db64bbb..5458776 100644
--- a/activerecord/test/cases/reflection_test.rb
+++ b/activerecord/test/cases/reflection_test.rb
@@ -184,6 +184,34 @@ class ReflectionTest < ActiveRecord::TestCase
     assert_kind_of ActiveRecord::Reflection::ThroughReflection, Subscriber.reflect_on_association(:books)
   end
 
+  def test_belongs_to_association_defines_has_associated_object_method
+    Company.belongs_to :foo
+    company = Company.new
+    assert company.respond_to?(:has_foo?)
+    assert company.respond_to?(:has_foo)
+  end
+
+  def test_has_one_association_defines_has_associated_object_method
+    Company.has_one :foo
+    company = Company.new
+    assert company.respond_to?(:has_foo?)
+    assert company.respond_to?(:has_foo)
+  end
+
+  def test_has_many_association_defines_has_associated_object_method
+    Company.has_many :foos
+    company = Company.new
+    assert company.respond_to?(:has_foos?)
+    assert company.respond_to?(:has_foos)
+  end
+
+  def test_has_and_belongs_to_many_association_defines_has_associated_object_method
+    Company.has_and_belongs_to_many :foos
+    company = Company.new
+    assert company.respond_to?(:has_foos?)
+    assert company.respond_to?(:has_foos)
+  end
+
   private
     def assert_reflection(klass, association, options)
       assert reflection = klass.reflect_on_association(association)
-- 
1.6.0.5