public static String getSessionIdentifier(Credentials credentials) {

        // Return the session identifier from the request params, if set, or
        // null otherwise
        return credentials != null ? credentials.getParameter(AUTH_SESSION_QUERY_PARAM) : null;
    }
Return the value of the session identifier associated with the given
credentials, or null if no session identifier is found in the
credentials.

@param credentials
    The credentials from which to extract the session identifier.

@return
    The session identifier associated with the given credentials, or
    null if no identifier is found.
extensions/guacamole-auth-sso/modules/guacamole-auth-sso-saml/src/main/java/org/apache/guacamole/auth/saml/AuthenticationProviderService.java