import com.sun.jmx.snmp.internal.SnmpAccessControlModel; //导入依赖的package包/类
AcmChecker(SnmpMibRequest req) {
    engine = (SnmpEngineImpl) req.getEngine();
    //We are in V3 architecture, ACM is in the picture.
    if(engine != null) {
        if(engine.isCheckOidActivated()) {
            try {
                if (SNMP_ADAPTOR_LOGGER.isLoggable(Level.FINEST)) {
                    SNMP_ADAPTOR_LOGGER.logp(Level.FINEST,
                            SnmpMib.class.getName(),
                            "AcmChecker(SnmpMibRequest)",
                            "SNMP V3 Access Control to be done");
                }
                model = (SnmpAccessControlModel)
                    engine.getAccessControlSubSystem().
                    getModel(SnmpDefinitions.snmpVersionThree);
                principal = req.getPrincipal();
                securityLevel = req.getSecurityLevel();
                pduType = req.getPdu().type;
                version = req.getRequestPduVersion();
                securityModel = req.getSecurityModel();
                contextName = req.getAccessContextName();
                l = new LongList();
                if (SNMP_ADAPTOR_LOGGER.isLoggable(Level.FINEST)) {
                    final StringBuilder strb = new StringBuilder()
                    .append("Will check oid for : principal : ")
                    .append(principal)
                    .append("; securityLevel : ").append(securityLevel)
                    .append("; pduType : ").append(pduType)
                    .append("; version : ").append(version)
                    .append("; securityModel : ").append(securityModel)
                    .append("; contextName : ").append(contextName);
                    SNMP_ADAPTOR_LOGGER.logp(Level.FINEST,
                            SnmpMib.class.getName(),
                            "AcmChecker(SnmpMibRequest)", strb.toString());
                }

            }catch(SnmpUnknownModelException e) {
                if (SNMP_ADAPTOR_LOGGER.isLoggable(Level.FINEST)) {
                    SNMP_ADAPTOR_LOGGER.logp(Level.FINEST,
                            SnmpMib.class.getName(),
                            "AcmChecker(SnmpMibRequest)",
                            "Unknown Model, no ACM check.");
                }
            }
        }
    }
}