throw new CrawlerSystemException("CrawlerClient instance is null. Cannot register null client.");
        }
        clientMap.put(Pattern.compile(regex), client);
    }

    /**
     * Adds a client with a regular expression pattern at a specific position.
     * @param regex The regular expression to match URLs.
     * @param client The CrawlerClient instance.
     * @param pos The position to add the client.
     */

            !item.equals(item.toString()));
      }
    }
  }

  /**
   * Class used to test whether equals() correctly handles an instance of an incompatible class.
   * Since it is a private inner class, the invoker can never pass in an instance to the tester
   */
  private enum NotAnInstance {
    EQUAL_TO_NOTHING;
  }

  public <S extends Comparable<?>> Ordering<S> reverse() {
    return (Ordering<S>) ReverseNaturalOrdering.INSTANCE;
  }

  // preserving singleton-ness gives equals()/hashCode() for free
  private Object readResolve() {
    return INSTANCE;
  }

  @Override
  public String toString() {
    return "Ordering.natural()";
  }

  private NaturalOrdering() {}

    for (Constructor<X> constructor : preferringStringsThenThrowables(constructors)) {
      X instance = newFromConstructor(constructor, cause);
      if (instance != null) {
        if (instance.getCause() == null) {
          instance.initCause(cause);
        }
        return instance;
      }
    }
    throw new IllegalArgumentException(
        "No appropriate constructor for exception of type "

        assertTrue(pairs.get(0) instanceof AvFlags, "First pair should be AvFlags instance");

        // Check second pair (AvTimestamp)
        assertEquals(AvPair.MsvAvTimestamp, pairs.get(1).getType(), "Second pair should be MsvAvTimestamp");
        assertTrue(pairs.get(1) instanceof AvTimestamp, "Second pair should be AvTimestamp instance");

        // Check third pair (AvTargetName)

   *
   * @since 13.0
   * @since 4.0 (in Equivalences)
   */
  public static Equivalence<Object> identity() {
    return Identity.INSTANCE;
  }

  static final class Equals extends Equivalence<Object> implements Serializable {

    static final Equals INSTANCE = new Equals();

    @Override
    protected boolean doEquivalent(Object a, Object b) {
      return a.equals(b);
    }

    @Override

  }

  private <T> T pickInstance(T[] instances, T defaultValue) {
    return pickInstance(Arrays.asList(instances), defaultValue);
  }

  private <T> T pickInstance(Collection<T> instances, T defaultValue) {
    if (instances.isEmpty()) {
      return defaultValue;
    }
    // generateInt() is 1-based.
    return Iterables.get(instances, (generateInt() - 1) % instances.size());
  }

 * system. Custom scope annotations should be annotated with {@code @Scope}.
 * <p>
 * Built-in scopes include:
 * <ul>
 *   <li>{@link Singleton} - One instance per container</li>
 *   <li>{@link SessionScoped} - One instance per Maven session</li>
 *   <li>{@link MojoExecutionScoped} - One instance per plugin execution</li>
 * </ul>
 *
 * @see Singleton
 * @see SessionScoped
 * @see MojoExecutionScoped
 * @since 4.0.0
 */

    protected DocumentBuilderFactoryUtil() {
    }

    /**
     * Returns a new instance of {@link DocumentBuilderFactory}.
     *
     * @return A new instance of {@link DocumentBuilderFactory}.
     */
    public static DocumentBuilderFactory newInstance() {
        return newInstance(false);
    }

    /**
     * Returns a new instance of {@link DocumentBuilderFactory}.
     *
     * @param external

    @SuppressWarnings("unchecked")
    /**
     * Creates a validator instance for form validation.
     * This method uses the system helper to create a validator with Fess-specific messages.
     *
     * @return a new action validator instance
     */
    @Override
    public ActionValidator<FessMessages> createValidator() {