Hi, FYI we have created together with Karl Pauls a library of wrappers for the JCR API, that in theory allows one to intercept JCR calls for various purposes.
I'm saying "in theory" as it's an early version that hasn't been tested much so far, but worked in simple use cases like pre-loading and simulating JCR content. The code is at https://github.com/apache/sling-whiteboard/tree/master/jcr-wrappers in the Sling whiteboard, if there's interest we might move it to Jackrabbit at some point (it has no Sling dependencies except a minor test library) but as we're both Sling committers it's easier for us to play with it there for now. -Bertrand
