JDO needs such a type-safe refactorable query API. However it is important that this does not go down the track followed by JPA Criteria queries (IMHO) since it leads to excessive code just to generate a query, hence the fluent approach make more sense. What we are proposing would be something similar to the following (taken from QueryDSL, but adapted to use more JDOQL-like syntax)
QCustomer customer = QCustomer.customer;
Query<Customer> q = pm.newTypesafeQuery(customer);
Customer bob = q.filter(customer.firstName.eq("Bob"))
where the QCustomer class is generated automatically (during compilation via an annotation processor, or optionally via a separate process when not using JDO annotations).
The idea is to provide support for all JDOQL syntax via this API, yet provide type-safe handling and refactorability, introducing this in the DataNucleus AccessPlatform 2.2 timeframe, and finally to standardise something similar into JDO 3.1. Your ideas/comments are welcome.