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= Analysis =

== Overview ==
This group of tasks is about improving the base.persistence module and providing a well-designed, easily usable and extensible persistence library. After this task is complete, the following will be true:
 * The base.persistence module will provide all the commons needed for persistence.
 * The intermediate storage format will be improved where needed.
 * A format registry tracking all current formats and their abilities to save/load will be present.
 * Functionality for saving immutables and pro-things will be present.
 * Extensions and extension points will be introduced to simplify the usage of the library.
 * All the code related to persistence will conform to our code standards.

== Task requirements ==
 * Try to devise a way the SharedLoader and SharedSaver to be consistent (currently they are not - see the notes on the persistence discussion that was held on 2009-02-18).
  * Another option is to rename them so that people don't get confused by the similarity in their names.
 * See how and where the intermediate storage format will be used and improve where needed.
 * Define how properties and immutables will be persisted (a good idea is to store the immutables as string).
 * Implement the annotations that were discussed - @Persist, @Immutable (see the video of the discussion for more information on these):
  * @Persist allows saving of pro-things in different formats.
  * @Immutable handles persistence of immutables.
  * Both annotations are used by the savers to track what and how should be saved.
  * An annotation for things not to be persisted might be needed.
  * (Optional) Provide a class that handles all immutables coming from the JDK.
 * Provide extension points for registering formats and for savers and loaders.
 * Design and implement a format registry that keeps track of all formats and their features and limitations:
  * see [wiki:BASE_PERSISTENCE_FORMAT_REGISTRY_R0] for more ideas on that.
 * Ensure backward compatibility.
 * Consider forwards compatibility in the design.
 * (Optional) Provide a wiki page - [wiki:BASE_PERSISTENCE] with detailed documentation on the library created so that everyone can easily get into it.

== Task result ==
 * Source code
 * (Optional) Wiki page

== Implementation idea ==
 Watch the design discussion on persistence to get an idea of how things should be done.

== Related ==
[wiki:BASE_PERSISTENCE_COMMONS_R0][[BR]]
[wiki:BASE_PERSISTENCE_INTERMEDIATE_STORAGE_R0][[BR]]
[wiki:BASE_PERSISTENCE_FORMAT_REGISTRY_R0][[BR]]
[wiki:BASE_PERSISTENCE_PROPERTY_FORMAT_R0][[BR]]
[wiki:BASE_PERSISTENCE_IMMUTABLES_R0][[BR]]
[wiki:BASE_PERSISTENCE_FORMAT_POINT_R0][[BR]]
http://asteasolutions.net/videos/

== How to demo ==
  * Explain the ideas of the library.
  * Show the source code.
  * Run the tests/demos.
  * (Optional) Show the created wiki page.

= Design =
The org.sophie2.base.persistence module will provide an extension point for formats via the BasePersistenceModule class. Each format should inherit PersistFormat and implement its abstract methods. Two additional methods will be provided - getSaver(Class<T extends Resource> saverClass) which returns a saver for a given type of resource and createLoader(Class<T extends Resource> loaderClass) which returns a loader for each resource of type T. Saving and loading of books should be implemented via the getSaver(Book.class) and createLoader(Book.class) methods. A default saver and loader might be provided in the future. The format registry should be easy to implement - it just has to track the registered extensions.

= Implementation =
^Describe and link the implementation results here (from the wiki or the repository).

= Testing =
^Place the testing results here.

= Comments =
^Write comments for this or later revisions here.