Added MultiJson.with_adapter method

Author: rwz

lib/multi_json.rb

@@ -117,6 +117,13 @@ def dump(object, options={})
     # :nodoc:
     alias :encode :dump
 
+    def with_adapter(new_adapter)
+      old_adapter, self.adapter = adapter, new_adapter
+      yield
+    ensure
+      self.adapter = old_adapter
+    end
+
   end
 
 end

spec/multi_json_spec.rb

@@ -78,6 +78,14 @@
     end
   end
 
+  it 'can set adapter for a block' do
+    MultiJson.use :ok_json
+    MultiJson.with_adapter(:json_pure) do
+      expect(MultiJson.adapter.name).to eq 'MultiJson::Adapters::JsonPure'
+    end
+    expect(MultiJson.adapter.name).to eq 'MultiJson::Adapters::OkJson'
+  end
+
   %w(json_gem json_pure nsjsonserialization oj ok_json yajl).each do |adapter|
     next if !macruby? && adapter == 'nsjsonserialization'
     next if jruby? && (adapter == 'oj' || adapter == 'yajl')