### Use cases: external service { #use-cases-external-service }

An example could be that you have an external authentication provider that you need to call.

You send it a token and it returns an authenticated user.

This provider might be charging you per request, and calling it might take some extra time than if you had a fixed mock user for tests.

  private int max = -1;

  /** Construct a new sparse array builder. */
  public CharEscaperBuilder() {
    this.map = new HashMap<>();
  }

  /** Add a new mapping from an index to an object to the escaping. */
  @CanIgnoreReturnValue
  public CharEscaperBuilder addEscape(char c, String r) {
    map.put(c, checkNotNull(r));
    if (c > max) {
      max = c;
    }
    return this;
  }

    /**
     * Constructs an unconnected NbtSocket.
     */
    public NbtSocket() {
    }

    /**
     * Constructs an NbtSocket and connects it to the specified NetBIOS address and port.
     *
     * @param address the NetBIOS address to connect to
     * @param port the port number, or 0 for the default NetBIOS session service port
     * @throws IOException if an I/O error occurs while creating the socket
     */

   * info.
   *
   * @throws IllegalArgumentException if {@code startNode} is not an element of the graph
   */
  public final Iterable<N> breadthFirst(N startNode) {
    return breadthFirst(ImmutableSet.of(startNode));
  }

  /**
   * Returns an unmodifiable {@code Iterable} over the nodes reachable from any of the {@code

   * java.io.Serializable} instance, and is thus declared an {@code Object}. For example, it might
   * be declared as a {@code List}.
   *
   * <p>Note also that serialization is not in general required to return an object that is
   * {@linkplain Object#equals equal} to the original, nor is it required to return even an object
   * of the same class. For example, if sublists of {@code MyList} instances were serializable,

 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

 *     this type, so it is safe to cast an {@code Optional<T>} to {@code Optional<S>} for any
 *     supertype {@code S} of {@code T}.
 * @author Kurt Alfred Kluever
 * @author Kevin Bourrillion
 * @since 10.0
 */
@DoNotMock("Use Optional.of(value) or Optional.absent()")
@GwtCompatible
public abstract class Optional<T> implements Serializable {
  /**
   * Returns an {@code Optional} instance with no contained reference.
   *

```

- Restart the server.
- Configure an [OAuth service provider](https://docs.wso2.com/display/IS540/Adding+and+Configuring+a+Service+Provider).

MinIO now includes support for using an Access Management Plugin. This is to allow object storage access control to be managed externally via a webhook.

   * necessarily indicate application-layer success: `response` may still indicate an unhappy HTTP
   * response code like 404 or 500.
   *
   * @throws IOException if the request could not be executed due to cancellation, a connectivity
   *     problem or timeout. Because networks can fail during an exchange, it is possible that the
   *     remote server accepted the request before the failure.