protected static FederationOptions readFederationOptions(Element sourceElement) {
        Element optionsElement = XML.getChild(sourceElement, FederationOptionsBuilder.federationOptionsElement);
        if (optionsElement == null) {
            return new FederationOptions();
        } else {
            return new FederationOptionsBuilder(optionsElement).build();
        }
    }
@author Tony Vaagenes
@author gjoranv
Base functionality for all target chain builders (provider, source)
config-model/src/main/java/com/yahoo/vespa/model/builder/xml/dom/chains/search/DomGenericTargetBuilder.java