protected synchronized VOMSACValidator getValidator(){
if (validator == null){
VOMSListener l = new VOMSListener();
VOMSTrustStore ts = VOMSTrustStores.newTrustStore(
Arrays.asList(DefaultVOMSTrustStore.DEFAULT_VOMS_DIR),
TimeUnit.MINUTES.toMillis(30),
l);
X509CertChainValidatorExt certChainValidator = PAPConfiguration.instance().getCertchainValidator();