There are couple of ways to achieve & deponds on your use case. You should go with adoptTo. The various options are
* Using jcr api look for a properties cq:lastReplicationAction, cq:lastReplicatedBy, cq:lastReplicated
* You can adopt to replicationStatus. http://dev.day.com/docs/en/cq/5-5/javadoc/com/day/cq/replication/ReplicationStatus.html
Ex:- ReplicationStatus rs = res.adaptTo(ReplicationStatus.class);
Please don't use the JCR API directly, if you can leverage the more highlevel services, which deliver the same information. The JCR representation of this information might be subject to change without further notice in a new version.