I'm trying to achieve the following: basically just coping a mongodb document and add a timestamp field to it in order to reconstruct the order in which the document was altered and in case if needed to restore these entries.
My approach is the following:
@Salat
trait Version[A <: DBEntity] extends ModelCompanion[A, ObjectId] {
def timeStamp: Long = System.currentTimeMillis()
/**
* this method overrides the default salat dao save method in order to make a copy for versioning of Objects
*/
override def save(entity: A) =
{
if (entity.id != null) {
// let salat deserialze the case class into a DBObject
val dbo = dao._grater.asDBObject(entity)
//convert the Object into a Map and append our timestamp
val builder = BasicDBObjectBuilder.start(dbo.toMap()).add("timeStamp", timeStamp)
val copyCollection = MongoDBLayer.mongoDB("history")
//and save it in the historic collection
copyCollection.insert(builder.get())
}
//delegate to the superclass to perform the actual save process
val wr = dao.save(entity)
wr
}
}
Is there a more elegant /convienent way to do it?
Or how would your approach be?
Thanks in advance,
Stefan
See SalatDAO#decorateDBO
- this method is called before every insert/save/update. This could be a logical place to park the code that adds a timestamp to your DBO and saves a copy in your history collection. Just override it and call super.decorateDBO at the beginning. Then proceed to add your timestamp and do whatever else you need to do.
/** A central place to modify DBOs before inserting, saving, or updating.
* @param toPersist object to be serialized
* @return decorated DBO for persisting
*/
def decorateDBO(toPersist: ObjectType) = {
val dbo = _grater.asDBObject(toPersist)
if (forceTypeHints) {
// take advantage of the mutability of DBObject by cramming in a type hint
dbo(ctx.typeHintStrategy.typeHint) = ctx.typeHintStrategy.encode(toPersist.getClass.getName).asInstanceOf[AnyRef]
}
dbo
}
(Also DBOs are mutable so there is no need to make call toMap
. You can just directly assign the timestamp to dbo("timestamp")
)