private boolean paramIsAllowed(String param) {
        
        // If allowed parameters are defined and not empty,
        // check to see if this parameter is allowed.
        if (allowedParams != null && !allowedParams.isEmpty() && !allowedParams.contains(param))
            return false;
        
        // If denied parameters are defined and not empty,
        // check to see if this parameter is denied.
        if (deniedParams != null && !deniedParams.isEmpty() && deniedParams.contains(param))
            return false;
        
        // By default, the parameter is allowed.
        return true;
        
    }
For a given parameter, check to make sure the parameter is allowed to be
used in the connection configuration, first by checking to see if
allowed parameters are defined and the given parameter is present, then
by checking for explicitly denied parameters. Returns false if the
configuration prevents the parameter from being used, otherwise true.

@param param
    The name of the parameter to check.

@return 
    False if the configuration prevents the parameter from being used,
    otherwise true.
extensions/guacamole-auth-quickconnect/src/main/java/org/apache/guacamole/auth/quickconnect/utility/QCParser.java