# See the License for the specific language governing permissions and
# limitations under the License.
-# Offers services to serialize a Nit objects to different persistent formats
+# Abstract services to serialize Nit objects to different formats
+#
+# This module declares the `auto_serializable` annotation to mark Nit classes as serializable.
+# For an introduction to this service, refer to the documentation of the `serialization` group.
+# This documentation provides more technical information on interesting entitie of this module.
+#
+# Interesting entities for end users of serializable classes:
+#
+# * Serialize an instance subclass of `Serializable` with either
+# `Serializer::serializable` and `Serializable::serialize`.
+# * Deserialize an object using `Deserializer::deserialize`.
+# The object type must the be checked with an `assert` or otherwise.
+#
+# Interesting entities to create custom serializable classes:
+#
+# * Subclass `Serializable` to declare a class as serializable and to customize
+# the serialization and deserialization behavior.
+# * Redefine `Serializable::core_serialize_to` to customize the serialization
+# of the receiver class.
+# * Redefine `Deserializer::deserialize_class` to customize the deserialization
+# of a specific class by name.
+#
+# Interesting entities for serialization format:
+#
+# * Subclass `Serializer` and `Deserializer` with custom serices.
+# * In `Serializer`, `serialize` and `serialize_reference` must be redefined.
+# * In `Deserializer`; `deserialize`, `deserialize_attribute and
+# `notify_of_creation` must be redefined.
module serialization is
new_annotation auto_serializable
end
# Abstract serialization service to be sub-classed by specialized services.
interface Serializer
- # Main method of this service, serialize the `object`
+ # Entry point method of this service, serialize the `object`
+ #
+ # This method, and refinements, should handle `null` and probably
+ # use double dispatch to customize the bahavior per serializable objects.
fun serialize(object: nullable Serializable) is abstract
- # Serialize an object as a "possible" reference, depending of the service
fun serialize_reference(object: Serializable) is abstract
+ # Serialize an object, with full serialization or a simple reference
- # Serialize an attribute, used by `Serializable::core_serialize_to`
+ # Serialize an attribute to compose a serializable object
+ #
+ # This method should be called from `Serializable::core_serialize_to`.
fun serialize_attribute(name: String, value: nullable Object)
do
if not try_to_serialize(value) then
# to be implemented by sub-classes
fun notify_of_creation(new_object: Object) is abstract
- # Mainly generated method to return the next instance of the givent
- # class by name
+ # Deserialize the next available object as an instance of `class_name`
+ #
+ # Returns the deserialized object on success, aborts on error.
+ #
+ # This method should be redefined for each custom subclass of `Serializable`.
+ # All refinement should look for a precise `class_name` and call super
+ # on unsupported classes.
fun deserialize_class(class_name: String): Object do
print "Error: doesn't know how to deserialize class \"{class_name}\""
abort
# Instances of this class can be passed to `Serializer::serialize`
interface Serializable
- # Full or true serialization
- fun serialize_to(v: Serializer) do v.serialize(self)
-
- # Body of the serialization of this class
- # Can be redefed in sub classes and refinements
- fun core_serialize_to(v: Serializer) do end
-
- # Whether full serialization (calls `serialize_to`) or place only references
- fun serialize_to_or_delay(v: Serializer) do v.serialize_reference(self)
+ # Serialize `self` to `serializer`
+ #
+ # This is a shortcut to `Serializer::serialize`.
+ fun serialize_to(serializer: Serializer) do serializer.serialize(self)
+
+ # Actual serialization of `self` to `serializer`
+ #
+ # This writes the full data of `self` to `serializer`.
+ #
+ # This method can be redefined in sub classes and refinements.
+ # It should use `Serializer::serialize_attribute` to to register real or
+ # logical attributes.
+ #
+ # Any refinement should have its equivalent refinement of
+ # `Deserializer::deserialize_class` to support this custom deserialization.
+ fun core_serialize_to(serializer: Serializer) do end
+
+ # Accept references or force direct serialization (using `serialize_to`)
+ #
+ # The subclass change the default behavior, which will accept references,
+ # to force to always serialize copies of `self`.
+ private fun serialize_to_or_delay(v: Serializer) do v.serialize_reference(self)
end
# Instances of this class are not delayed and instead serialized immediately