try {
      assertFalse("add(present) should return false or throw", collection.add(e0()));
    } catch (UnsupportedOperationException tolerated) {
    }
    expectUnchanged();
  }

  @CollectionFeature.Require(
      value = {SUPPORTS_ADD, ALLOWS_NULL_VALUES},
      absent = RESTRICTS_ELEMENTS)
  public void testAdd_nullSupported() {
    assertTrue("add(null) should return true", collection.add(null));
    expectAdded((E) null);

    return doAssertThrows(expectedThrowable, supplier, /* userPassedSupplier= */ true);
  }

  @CanIgnoreReturnValue
  static <T extends Throwable> T assertThrows(
      Class<T> expectedThrowable, ThrowingRunnable runnable) {
    return doAssertThrows(
        expectedThrowable,
        () -> {
          runnable.run();
          return null;
        },

    try {
      assertFalse("add(present) should return false or throw", collection.add(e0()));
    } catch (UnsupportedOperationException tolerated) {
    }
    expectUnchanged();
  }

  @CollectionFeature.Require(
      value = {SUPPORTS_ADD, ALLOWS_NULL_VALUES},
      absent = RESTRICTS_ELEMENTS)
  public void testAdd_nullSupported() {
    assertTrue("add(null) should return true", collection.add(null));
    expectAdded((E) null);

   *
   * @return {@code true} if the graph was modified as a result of this call
   */
  @CanIgnoreReturnValue
  boolean removeNode(N node);

  /**
   * Removes the edge connecting {@code nodeU} to {@code nodeV}, if it is present.
   *
   * @return the value previously associated with the edge connecting {@code nodeU} to {@code

    @Override
    int writeBodyWireFormat(final byte[] dst, final int dstIndex) {
        return 0;
    }

    @Override
    int readBodyWireFormat(final byte[] src, final int srcIndex) {
        return readResourceRecordWireFormat(src, srcIndex);
    }

    @Override
    int writeRDataWireFormat(final byte[] dst, final int dstIndex) {
        return 0;
    }

    @Override

        public String getQuery() {
            return null;
        }

        @Override
        public Map<String, String[]> getFields() {
            return null;
        }

        @Override
        public Map<String, String[]> getConditions() {
            return null;
        }

        @Override
        public String[] getLanguages() {
            return null;
        }

        @Override

        assertNull(delegatingConfig.getRandom(), "Should return null when delegate returns null");
        assertNull(delegatingConfig.getLocalAddr(), "Should return null when delegate returns null");
        assertNull(delegatingConfig.getNetbiosHostname(), "Should return null when delegate returns null");
        assertNull(delegatingConfig.getResolveOrder(), "Should return null when delegate returns null");

        return accessTokenList;
    }

    /**
     * Get the access token.
     * @param id The ID of the access token.
     * @return The access token.
     */
    public OptionalEntity<AccessToken> getAccessToken(final String id) {
        return accessTokenBhv.selectByPK(id);
    }

    /**
     * Store the access token.

     * @return a configured instance of {@link XPath}.
     * @throws CrawlerSystemException if an error occurs while creating the {@link XPath} instance.
     */
    public XPath createXPath(final Consumer<XPathFactory> builder) {
        try {
            final XPathFactory factory = XPathFactory.newInstance();
            builder.accept(factory);
            return factory.newXPath();

     * and user authentication status.
     *
     * @return true if login is required, false otherwise
     */
    protected boolean isLoginRequired() {
        if (fessConfig.isLoginRequired() && !fessLoginAssist.getSavedUserBean().isPresent()) {
            return true;
        }
        return false;
    }

    /**