}

  /**
   * Returns the string if it is not null, or an empty string otherwise.
   *
   * @param string the string to test and possibly return
   * @return {@code string} if it is not null; {@code ""} otherwise
   */
  static String nullToEmpty(@Nullable String string) {
    return (string == null) ? "" : string;
  }

  /**
   * Returns the string if it is not empty, or a null string otherwise.
   *

     *
     * @param date the date to format
     * @return formatted date string, or empty string if date is null
     */
    public static String formatDate(final Date date) {
        if (date == null) {
            return StringUtil.EMPTY;
        }
        final SimpleDateFormat sdf = new SimpleDateFormat(Constants.ISO_DATETIME_FORMAT);

    }

    /**
     * Test putResultDataBody with empty array
     */
    @Test
    public void test_putResultDataBody_withEmptyArray() {
        TestFessTransformer transformer = new TestFessTransformer();
        Map<String, Object> dataMap = new HashMap<>();

        transformer.putResultDataBody(dataMap, "empty", "value1");

        String[] emptyArray = new String[] {};

        assertEquals(Long.valueOf(5), facetInfo.minDocCount);
        assertEquals("count.desc", facetInfo.sort);
        assertEquals("unknown", facetInfo.missing);
    }

    // Test init with empty fields
    @Test
    public void test_init_withEmptyFields() {
        FessConfig fessConfig = new FessConfig.SimpleImpl() {
            @Override
            public String getQueryFacetFields() {

    }

    @Test
    @DisplayName("Test readParametersWireFormat with empty buffer")
    void testReadParametersWireFormatEmptyBuffer() throws Exception {
        byte[] buffer = new byte[0];

        // Empty buffer adds one empty FileNotifyInformation
        int result = response.readParametersWireFormat(buffer, 0, 0);
        assertEquals(0, result);

	}

	// There are two possibilities:
	// - We use a KMS -> There must be non-empty key ID and a KMS data key.
	// - We use a K/V -> There must be no key ID and no KMS data key.
	// Otherwise, the caller has passed an invalid argument combination.
	if keyID == "" && len(kmsKey) != 0 {
		logger.CriticalIf(context.Background(), errors.New("The key ID must not be empty if a KMS data key is present"))
	}
	if keyID != "" && len(kmsKey) == 0 {

    StringSubscriber s2 = new StringSubscriber();
    ObjectSubscriber o1 = new ObjectSubscriber();

    Iterator<Subscriber> empty = registry.getSubscribers("");
    assertFalse(empty.hasNext());

    empty = registry.getSubscribers("");

    registry.register(s1);
    assertFalse(empty.hasNext());

    Iterator<Subscriber> one = registry.getSubscribers("");
    assertEquals(s1, one.next().target);

        assertEquals("\\*\\*\\*\\?\\?\\?", escaped5);

        // Test empty string
        String query6 = "";
        String escaped6 = SuggestUtil.escapeWildcardQuery(query6);
        assertEquals("", escaped6);
    }

    @Test
    public void testGetAsListWithEmptyList() {
        // Test with empty list
        List<String> emptyList = new ArrayList<>();

  }

  /**
   * Returns an empty immutable range map.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings("unchecked")
  public static <K extends Comparable<?>, V> ImmutableRangeMap<K, V> of() {
    return (ImmutableRangeMap<K, V>) EMPTY;
  }

  /** Returns an immutable range map mapping a single range to a single value. */

		</c:if>
		<c:if test="${not empty forumLink}">
			<li class="nav-item" data-toggle="tooltip" data-placement="left"
				title="<la:message key="labels.tooltip_forum" />"><a class="nav-link" href="${forumLink}" target="_forum" aria-label="<la:message key="labels.tooltip_forum" />"><i class="fas fa-comments" aria-hidden="true"></i></a></li>
		</c:if>
		<c:if test="${not empty helpLink}">