protected static final String ALLINURL_FIELD_PREFIX = "allinurl:";

    /** Prefix for queries that search only in title fields. */
    protected static final String ALLINTITLE_FIELD_PREFIX = "allintitle:";

    /** The OpenSearch query builder used for executing the search. */
    protected QueryBuilder queryBuilder;

    /** List of sort builders to apply to the search query. */

     * Checks if a value represents an occurrence-based search modifier.
     * Currently supports "allintitle" and "allinurl" modifiers.
     *
     * @param value the value to check
     * @return true if the value is an occurrence modifier, false otherwise
     */
    protected boolean isOccurrence(final String value) {
        return "allintitle".equals(value) || "allinurl".equals(value);
    }

    /**

					<select id="as_occt" name="as.occt" class="form-control">
						<option value=""><la:message key="labels.advance_search_occt_default" /></option>
						<option value="allintitle" <c:if test="${as.occt.contains('allintitle')}">selected</c:if>><la:message
								key="labels.advance_search_occt_allintitle"
							/></option>
						<option value="allinurl" <c:if test="${as.occt.contains('allinurl')}">selected</c:if>><la:message

					<select id="as_occt" name="as.occt" class="form-control">
						<option value=""><la:message key="labels.advance_search_occt_default" /></option>
						<option value="allintitle" <c:if test="${as.occt.contains('allintitle')}">selected</c:if>><la:message
								key="labels.advance_search_occt_allintitle"
							/></option>
						<option value="allinurl" <c:if test="${as.occt.contains('allinurl')}">selected</c:if>><la:message