Note: Before reading further be sure to read the introductory tutorial.
With the new lock and its implementation
introduced in version 1.1 there now is the possibility to prefer
certain lock request. If a lock is not directly available
a preferred lock request will be fulfilled before any other request
that is not preferred.
Putting preferences on certain lock levels is what the read/write
lock manager and the read/write/upgrade
lock manager with their respective implementations for read/write
For full flexibility there is an option to specify preference for any
locking request both in the lock
manager as well as in the lock.