Some code cleaning which was in #476

lib/neo4j/shared/property.rb

@@ -39,16 +39,15 @@ def read_attribute(name)
 
     def default_properties=(properties)
       keys = self.class.default_properties.keys
-      @default_properties = properties.reject{|key| !keys.include?(key)}
+      @default_properties = properties.select {|key| keys.include?(key) }
     end
 
     def default_property(key)
-      keys = self.class.default_properties.keys
-      keys.include?(key.to_sym) ? default_properties[key.to_sym] : nil
+      default_properties[key.to_sym]
     end
 
     def default_properties
-      @default_properties ||= {}
+      @default_properties ||= Hash.new(nil)
       # keys = self.class.default_properties.keys
       # _persisted_obj.props.reject{|key| !keys.include?(key)}
     end
@@ -173,8 +172,8 @@ def default_properties
       end
 
       def default_property_values(instance)
-        default_properties.inject({}) do |result,pair|
-          result.tap{|obj| obj[pair[0]] = pair[1].call(instance)}
+        default_properties.each_with_object({}) do |(key, block),result|
+          result[key] = block.call(instance)
         end
       end