Replace validators code duplications with macro

The code implementing the functionality of caching validators
and getting them was duplicated all over the validator classes.
These duplications are now replaced by a respective macro defined
in the validators base class.

Change-Id: I3d44811b75159b48769a65f37e14c6ea99f434d0

git-svn-id: https://svn.apache.org/repos/asf/etch/trunk@1679584 13f79535-47bb-0310-9956-ffa450edef68
22 files changed