question: @ Override public ByteString normalizeAttributeValue ( final Schema schema , final ByteSequence value ) throws DecodeException { final BigInteger serialNumber ; final String dnstring ; try { CertificateFactory certFactory = CertificateFactory . getInstance ( "X.509" ) ; InputStream inputStream = new ByteArrayInputStream ( value . toByteArray ( ) ) ; X509Certificate certValue = ( X509Certificate ) certFactory . generateCertificate ( inputStream ) ; serialNumber = certValue . getSerialNumber ( ) ; X500Principal issuer = certValue . getIssuerX500Principal ( ) ; dnstring = issuer . getName ( X500Principal . RFC2253 ) ; } catch ( CertificateException ce ) { final LocalizableMessage message = ERR_MR_CERTIFICATE_MATCH_PARSE_ERROR . get ( ce . getMessage ( ) ) ; logger . trace ( message ) ; return value . toByteString ( ) ; } final ByteString certificateIssuer = normalizeDN ( schema , dnstring ) ; return createEncodedValue ( serialNumber , certificateIssuer ) ; }
target:  Retrieves the normalized form of the provided value, which is best suited for efficiently performing matching operations on that value.