import jcifs.spnego.NegTokenInit;


/**
 * This class used to provide Kerberos feature when setup GSSContext.
 * 
 * @author Shun
 */
class Kerb5Context implements SSPContext {

    private static final Logger log = LoggerFactory.getLogger(Kerb5Context.class);

    private static final ASN1ObjectIdentifier KRB5_MECH_OID;
    private static final ASN1ObjectIdentifier KRB5_MS_MECH_OID;

#log4j.logger.jcifs.smb.DfsImpl: DEBUG
#log4j.logger.jcifs.smb: DEBUG
#log4j.logger.jcifs.smb.SmbFileOutputStream: TRACE
#log4j.logger.jcifs.smb.SigningDigest: TRACE

                Set<ASN1ObjectIdentifier> mechs = new HashSet<>(Arrays.asList(tok.getMechanisms()));
                boolean foundKerberos = false;
                for ( ASN1ObjectIdentifier mech : Kerb5Context.SUPPORTED_MECHS ) {
                    foundKerberos |= mechs.contains(mech);
                }
                if ( ( !foundKerberos || this.forceFallback ) && this.canFallback && tc.getConfig().isAllowNTLMFallback() ) {