private void computeAskForSum() {
        this.askForSummary = summaryRequestedInFill;
        if (askForSummary == null || askForSummary.equals(PRESENTATION)) {
            askForSummary = summaryFromQuery;
        }
        if (askForSummary == null) {
            askForSummary = DEFAULT_CLASS;
        }
        if (askForFields != null) {
            askForSummary = ALL_FIELDS_CLASS;
        }
    }
resolve summary class to use when none provided
container-search/src/main/java/com/yahoo/prelude/fastsearch/PartialSummaryHandler.java