/** The conditions. */
    public Map<String, String[]> as = new HashMap<>();

    /** The extra queries. */
    public String[] ex_q;

    /** The similar document hash. */
    public String sdh;

    @Override
    public String getQuery() {
        return q;
    }

    @Override
    public String[] getExtraQueries() {

     */
    @ValidateTypeFailure
    public Integer pn;

    /**
     * Similar document hash for finding related documents.
     */
    @Size(max = 1000)
    public String sdh;

    /**
     * Parameter to control tracking of total hits in search results.
     */
    @Size(max = 100)
    public String track_total_hits;

    /**
     * Default constructor for SearchForm.