[hibernate-dev] [HV/HSEARCH] Free form

[Emmanuel Bernard]

I took the flight home to play with free form and specifically how we would retrieve data from the free form structure.
By free-form I mean non POJO but they will have schema (not expressed here).

https://github.com/emmanuelbernard/hibernate-search/commit/0bd3fbab137bdad81bfa5b9934063792a050f537

And in particular
https://github.com/emmanuelbernard/hibernate-search/blob/freeform/freeform/src/main/java/org/hibernate/freeform/StructureTraverser.java
https://github.com/emmanuelbernard/hibernate-search/blob/freeform/freeform/src/main/java/org/hibernate/freeform/pojo/impl/PojoStructureTraverser.java

It probably does not compile, I could not make the build work.

I figured it was important to dump this raw thinking because it will influence and will be influenced by the redesign of the DocumentBuilder of Hibernate Search.

There are several options for traversing a free form structure 
- expose  the traversing API as a holder to  navigate all properties per structure and sub structure. This is what the prototype shows. Caching needs to be accessed via a hashmap get or other lookup. Metadata and the traversing structure will be navigated in parallel
- expose a structure that is specialized to a single property or container unwrapping aspect. The structures will be spread across and embedded in the Metadata


Another angle:
- create a traversable object per payload to carry it (sharing metadata info per type)
- have a stateless traversable object that is provided the payload for each access 

The former seems better as it does not create a traversable object per object navigated. 
The latter is better for payloads that need parsing or are better at sequential access since state could be cached. 

We need to discuss that and know where DocumentBuilder is going to properly design this API.

Emmanuel