public void setSessionStoreFactoryIfUndefined(final SessionStoreFactory sessionStoreFactory) {
        if (this.sessionStoreFactory == null) {
            setSessionStoreFactory(sessionStoreFactory);
        }
    }
<p>setSessionStoreFactoryIfUndefined.</p>

@param sessionStoreFactory a {@link SessionStoreFactory} object
pac4j-core/src/main/java/org/pac4j/core/config/Config.java