*/
    public void setDefaultField(final String defaultField) {
        this.defaultField = defaultField;
    }

    /**
     * Gets the set of highlighted query terms.
     * @return The set of highlighted query terms, or empty set if not initialized.
     */
    public Set<String> getHighlightedQuerySet() {
        return highlightedQuerySet != null ? highlightedQuerySet : new HashSet<>();
    }

    /**
     * Retrieves and displays cached content for a specific document.
     *
     * @param form the cache form containing document ID and highlight query
     * @return ActionResponse containing the cached document content or error redirect
     */
    @Execute
    public ActionResponse index(final CacheForm form) {

 */
public class CacheForm {

    /** Document ID for cache operations. */
    @Required
    @Size(max = 100)
    public String docId;

    /** Highlight query parameters. */
    public String[] hq;

    /** Search query parameter for error page. */
    public String q;

    /** Number of results parameter for error page. */
    public String num;

    /**
     * Returns the facet info.
     *
     * @return The facet info.
     */
    public abstract FacetInfo getFacetInfo();

    /**
     * Returns the highlight info.
     *
     * @return The highlight info.
     */
    public abstract HighlightInfo getHighlightInfo();

    /**
     * Returns the sort.
     *
     * @return The sort.
     */