adding a join factory method on the select manager

5 files changed, 17 insertions, 5 deletions

diff --git a/lib/arel.rb b/lib/arel.rb
index 6a8d9571d1..3d0648263b 100644
--- a/lib/arel.rb
+++ b/lib/arel.rb
@@ -1,4 +1,5 @@
 require 'arel/crud'
+require 'arel/factory_methods'
 
 require 'arel/expressions'
 require 'arel/predications'
diff --git a/lib/arel/factory_methods.rb b/lib/arel/factory_methods.rb
new file mode 100644
index 0000000000..23d668c8e5
--- /dev/null
+++ b/lib/arel/factory_methods.rb
@@ -0,0 +1,9 @@
+module Arel
+  ###
+  # Methods for creating various nodes
+  module FactoryMethods
+    def create_join from, to, on = nil, klass = Nodes::InnerJoin
+      klass.new(from, to, on)
+    end
+  end
+end
diff --git a/lib/arel/nodes/string_join.rb b/lib/arel/nodes/string_join.rb
index ea7912f92b..b24e91b6b8 100644
--- a/lib/arel/nodes/string_join.rb
+++ b/lib/arel/nodes/string_join.rb
@@ -3,8 +3,8 @@ module Arel
     class StringJoin < Arel::Nodes::Join
       undef :constraint
 
-      def initialize left, right
-        super(left, right, nil)
+      def initialize left, right, on = nil
+        super
       end
     end
   end
diff --git a/lib/arel/table.rb b/lib/arel/table.rb
index e7a626a4c6..ceb81705b3 100644
--- a/lib/arel/table.rb
+++ b/lib/arel/table.rb
@@ -1,6 +1,7 @@
 module Arel
   class Table
     include Arel::Crud
+    include Arel::FactoryMethods
 
     @engine = nil
     class << self; attr_accessor :engine; end
@@ -57,10 +58,10 @@ module Arel
       case relation
       when String, Nodes::SqlLiteral
         raise if relation.blank?
-        from Nodes::StringJoin.new(self, relation)
-      else
-        from klass.new(self, relation, nil)
+        klass = Nodes::StringJoin
       end
+
+      from create_join(self, relation, nil, klass)
     end
 
     def group *columns
diff --git a/lib/arel/tree_manager.rb b/lib/arel/tree_manager.rb
index 2fa770a0e3..5722baca77 100644
--- a/lib/arel/tree_manager.rb
+++ b/lib/arel/tree_manager.rb
@@ -2,6 +2,7 @@ module Arel
   class TreeManager
     # FIXME: Remove this.
     include Arel::Relation
+    include Arel::FactoryMethods
 
     attr_accessor :visitor
     attr_reader :ast, :engine