adding model adapter

Gemfile

@@ -1,16 +1,19 @@
 source "http://rubygems.org"
 
-# case ENV["MODEL_ADAPTER"]
-# when nil, "active_record"
-#   gem "sqlite3"
-#   gem "activerecord", :require => "active_record"
-#   gem "with_model"
-# when "data_mapper"
-#   gem "dm-core", "~> 1.0.2"
-#   gem "dm-sqlite-adapter", "~> 1.0.2"
-#   gem "dm-migrations", "~> 1.0.2"
-# else
-#   raise "Unknown model adapter: #{ENV["MODEL_ADAPTER"]}"
-# end
+case ENV["MODEL_ADAPTER"]
+when nil, "active_record"
+  gem "sqlite3"
+  gem "activerecord", :require => "active_record"
+  gem "with_model"
+when "data_mapper"
+  gem "dm-core", "~> 1.0.2"
+  gem "dm-sqlite-adapter", "~> 1.0.2"
+  gem "dm-migrations", "~> 1.0.2"
+when "mongoid"
+  gem "bson_ext", "~> 1.1"
+  gem "mongoid", "~> 2.0.0.beta.20"
+else
+  raise "Unknown model adapter: #{ENV["MODEL_ADAPTER"]}"
+end
 
 gemspec

lib/xapit.rb

@@ -62,6 +62,9 @@ def serialize_value(value)
 require 'xapit/client/facet'
 require 'xapit/client/facet_option'
 require 'xapit/client/remote_database'
+require 'xapit/client/model_adapters/abstract_model_adapter'
+require 'xapit/client/model_adapters/default_model_adapter'
+require 'xapit/client/model_adapters/active_record_adapter'
 require 'xapit/server/database'
 require 'xapit/server/query'
 require 'xapit/server/indexer'

lib/xapit/client/membership.rb

@@ -11,6 +11,10 @@ def xapit(&block)
           @xapit_index_builder.instance_eval(&block)
           include AdditionalMethods
         end
+
+        def model_adapter
+          @xapit_model_adapter ||= Xapit::Client::AbstractModelAdapter.adapter_class(self).new(self)
+        end
       end
 
       module AdditionalMethods

lib/xapit/client/model_adapters/abstract_model_adapter.rb

@@ -0,0 +1,22 @@
+module Xapit
+  module Client
+    class AbstractModelAdapter
+      def self.inherited(subclass)
+        @@subclasses ||= []
+        @@subclasses << subclass
+      end
+
+      def self.adapter_class(model_class)
+        @@subclasses.detect { |subclass| subclass.for_class?(model_class) } || DefaultModelAdapter
+      end
+
+      def self.for_class?(model_class)
+        false # override in subclass
+      end
+
+      def initialize(model_class)
+        @model_class = model_class
+      end
+    end
+  end
+end

lib/xapit/client/model_adapters/active_record_adapter.rb

@@ -0,0 +1,9 @@
+module Xapit
+  module Client
+    class ActiveRecordAdapter < AbstractModelAdapter
+      def self.for_class?(model_class)
+        model_class <= ActiveRecord::Base
+      end
+    end
+  end
+end

lib/xapit/client/model_adapters/default_model_adapter.rb

@@ -0,0 +1,7 @@
+module Xapit
+  module Client
+    class DefaultModelAdapter < AbstractModelAdapter
+      # This adapter is used when no matching adapter is found
+    end
+  end
+end

spec/xapit/client/membership_spec.rb

@@ -30,4 +30,8 @@
     @member_class.xapit { facet :foo }
     @member_class.search.clauses.should eq([{:in_classes => [@member_class]}, {:include_facets => [:foo]}])
   end
+
+  it "includes facets" do
+    @member_class.model_adapter.should be_kind_of(Xapit::Client::DefaultModelAdapter)
+  end
 end

spec/xapit/client/model_adapters/active_record_adapter_spec.rb

@@ -0,0 +1,23 @@
+if ENV["MODEL_ADAPTER"].nil? || ENV["MODEL_ADAPTER"] == "active_record"
+  require "spec_helper"
+
+  RSpec.configure do |config|
+    config.extend WithModel
+  end
+
+  ActiveRecord::Base.establish_connection(:adapter => "sqlite3", :database => ":memory:")
+
+  describe Xapit::Client::ActiveRecordAdapter do
+    with_model :article do
+      table do |t|
+        t.string "name"
+      end
+    end
+
+    it "is only for active record classes" do
+      Xapit::Client::ActiveRecordAdapter.should_not be_for_class(Object)
+      Xapit::Client::ActiveRecordAdapter.should be_for_class(Article)
+      Xapit::Client::AbstractModelAdapter.adapter_class(Article).should == Xapit::Client::ActiveRecordAdapter
+    end
+  end
+end

spec/xapit/client/model_adapters/default_model_adapter_spec.rb

@@ -0,0 +1,7 @@
+require "spec_helper"
+
+describe Xapit::Client::DefaultModelAdapter do
+  it "should be default for generic classes" do
+    Xapit::Client::DefaultModelAdapter.adapter_class(Object).should == Xapit::Client::DefaultModelAdapter
+  end
+end