Do you know of an ‘easy’ way to store and retrieve objects in Java without using a relational DB / ORM like Hibernate?
[Note that I am not considering serialization as-is for this purpose, as it won’t allow to retrieve arbitrary objects in the middle of an object graph. Neither am I considering DB4O because of its restrictive license. Thanks.]
‘Easy’ meaning: not having to handle low-level details such as key/value pairs to rebuild an object graph (as with BerkeleyDB or traditional caches). The same applies for rebuilding objects from a document- or column-oriented DB (CouchDB, HBase, …, even Lucene).
Perhaps there are interesting projects out there that provide a layer of integration between the mentioned storage systems and the object model (like ORM would be for RDBMSs) that I am not aware of.
Anyone successfully using those in production, or experimenting with persistence strategies other than relational DBs? How about RDF stores?
Update: I came across a very interesting article: A list of distributed key-value stores
I guess I have found a sort of answer to my question.
Getting the document-oriented paradigm mindset is no easy task when you have always thought your data in terms of relationships, normalization and joins.
CouchDB seems to fit the bill. It still could act as a key-value store but its great querying capabilities (map/reduce, view collations), concurrency readiness and language-agnostic HTTP access makes it my choice.
Only glitch is having to correclty define and map JSON structures to objects, but I’m confident I will come up with a simple solution for usage with relational models from Java and Scala (and worry about caching later on, as contention is moved away from the database). Terracotta could still be useful but certainly not as with an RDBMS scenario.
Thank you all for your input.