*
 * @since 17.0
 */
@GwtCompatible
public final class Verify {
  /**
   * Ensures that {@code expression} is {@code true}, throwing a {@code VerifyException} with no
   * message otherwise.
   *
   * @throws VerifyException if {@code expression} is {@code false}
   * @see Preconditions#checkState Preconditions.checkState()
   */
  public static void verify(boolean expression) {
    if (!expression) {

 *
 * @since 17.0
 */
@GwtCompatible
public final class Verify {
  /**
   * Ensures that {@code expression} is {@code true}, throwing a {@code VerifyException} with no
   * message otherwise.
   *
   * @throws VerifyException if {@code expression} is {@code false}
   * @see Preconditions#checkState Preconditions.checkState()
   */
  public static void verify(boolean expression) {
    if (!expression) {

   * 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.
   *

   * 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.
   *

      for any such Derivative Works as a whole, provided Your use,
      reproduction, and distribution of the Work otherwise complies with
      the conditions stated in this License.

   5. Submission of Contributions. Unless You explicitly state otherwise,
      any Contribution intentionally submitted for inclusion in the Work
      by You to the Licensor shall be under the terms and conditions of

    }

    /**
     * Checks if this item has been updated.
     * @return true if updated, false otherwise
     */
    public boolean isUpdated() {
        return newInput != null;
    }

    /**
     * Checks if this item has been deleted.
     * @return true if deleted, false otherwise
     */
    public boolean isDeleted() {
        return isUpdated() && newInput.length() == 0;
    }

  /**
   * Returns the value associated with {@code key} in this cache, obtaining that value from {@code
   * loader} if necessary. The method improves upon the conventional "if cached, return; otherwise
   * create, cache and return" pattern. For further improvements, use {@link LoadingCache} and its
   * {@link LoadingCache#get(Object) get(K)} method instead of this one.
   *

     *
     * @param protocols the protocols to use, in order of preference. If the list contains
     *     [Protocol.H2_PRIOR_KNOWLEDGE] then that must be the only protocol and HTTPS URLs will not
     *     be supported. Otherwise the list must contain [Protocol.HTTP_1_1]. The list must
     *     not contain null or [Protocol.HTTP_1_0].
     */
    fun protocols(protocols: List<Protocol>) =
      apply {

     *
     * @return true if the crawler is running, false otherwise
     */
    public boolean isCrawlerRunning() {
        return crawlerRunning;
    }

    /**
     * Sets the crawler running status.
     *
     * @param crawlerRunning true to indicate the crawler is running, false otherwise
     */
    public void setCrawlerRunning(final boolean crawlerRunning) {

     * Uses O(1) Set lookup for improved performance.
     *
     * @param field the field name to check
     * @return true if the field can be used for sorting, false otherwise
     */
    protected boolean isSortField(final String field) {
        return sortFieldSet != null && sortFieldSet.contains(field);
    }

    /**