lib/popcorn: introduce RepoObject in pop_repos

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>

diff --git a/lib/popcorn/pop_repos.nit b/lib/popcorn/pop_repos.nit
index c950ea4..f2d4a22 100644 (file)
--- a/lib/popcorn/pop_repos.nit
+++ b/lib/popcorn/pop_repos.nit
@@ -216,17 +216,14 @@ end
 #
 # ~~~
 # import popcorn
-# import popcorn::pop_routes
+# import popcorn::pop_repos
 #
 # # First, let's create a User abstraction:
 #
 # # Serializable user representation.
 # class User
+#      super RepoObject
 #      serialize
-#      super Jsonable
-#
-#      # User uniq ID
-#      var id: String = (new MongoObjectId).id is serialize_as "_id"
 #
 #      # User login
 #      var login: String
@@ -235,9 +232,6 @@ end
 #      var password: String is writable
 #
 #      redef fun to_s do return login
-#      redef fun ==(o) do return o isa SELF and id == o.id
-#      redef fun hash do return id.hash
-#      redef fun to_json do return serialize_to_json
 # end
 #
 # # We then need to subclass the `MongoRepository` to provide User specific services:
@@ -331,6 +325,62 @@ class MongoRepository[E: Serializable]
        end
 end
 
+# Base serializable entity that can go into a JsonRepository
+#
+# Provide boiler plate implementation of all object serializable to json.
+#
+# `id` is used as a primary key for `find_by_id`.
+#
+# Subclassing RepoObject makes it easy to create a serializable class:
+# ~~~
+# import popcorn::pop_repos
+#
+# class Album
+#      super RepoObject
+#      serialize
+#
+#      var title: String
+#      var price: Float
+# end
+# ~~~
+#
+# Do not forget the `serialize` annotation else the fields will not be serialized.
+#
+# It is also possible to redefine the `id` primary key to use your own:
+# ~~~
+# import popcorn::pop_repos
+#
+# class Order
+#      super RepoObject
+#      serialize
+#
+#      redef var id = "order-{get_time}"
+#
+#      # ...
+#
+# end
+# ~~~
+abstract class RepoObject
+       super Jsonable
+       serialize
+
+       # `self` unique id.
+       #
+       # This attribute is serialized under the key `_id` to be used
+       # as primary key by MongoDb
+       var id: String = (new MongoObjectId).id is writable, serialize_as "_id"
+
+       # Base object comparison on ID
+       #
+       # Because multiple deserialization can exists of the same instance,
+       # we use the ID to determine if two object are the same.
+       redef fun ==(o) do return o isa SELF and id == o.id
+
+       redef fun hash do return id.hash
+       redef fun to_s do return id
+       redef fun to_json do return serialize_to_json
+end
+
 # JsonObject can be used as a `RepositoryQuery`.
 #
 # See `mongodb` lib.