super(new EnumMap<K, V>(keyType), new HashMap<V, K>());
    // TODO: cpovirk - Pre-size the HashMap based on the number of enum values?
    this.keyTypeOrObjectUnderJ2cl = keyType;
  }

  // Overriding these 3 methods to show that values may be null (but not keys)

  @Override
  K checkKey(K key) {
    return checkNotNull(key);
  }

  @CanIgnoreReturnValue
  @Override

labels.virtual_host_value=Virtual Host
labels.append_query_param_enabled=Append Search Parameters
labels.login_required=Login Required
labels.result_collapsed=Collapse Duplicate Results
labels.login_link=Show Login Link
labels.thumbnail=Show Thumbnail
labels.ignore_failure_type=Ignore Failure Types
labels.failure_count_threshold=Failure Count Threshold
labels.popular_word_word_enabled=Popular Word Response
labels.supported_search_web=Web

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[22] *}

/// tip

All this might seem contrived. And it might not be very clear how is it useful yet.

These examples are intentionally simple, but show how it all works.

In the chapters about security, there are utility functions that are implemented in this same way.

If you understood all this, you already know how those utility tools for security work underneath.

                               aria-controls="listSearchForm"><i class="fas fa-search" aria-hidden="true"></i></a>
                            <div class="collapse <c:if test="${!empty name || !empty handlerName || !empty description}">show</c:if>" id="listSearchForm">
                                <la:form action="/admin/dataconfig/">
                                    <div class="form-group row">

    #   o diffIgnoredKeyList: list of ignored keys for differences (NotRequired)
    #   o maskedKeyList: list of masked keys for security (NotRequired)
    #   o isEnvOnlyFloatLeft: is it environment only? (and show as float-left?) (NotRequired)
    #   o extendsPropRequest: other request name of exnteds-properties (NotRequired)
    #   o isCheckImplicitOverride: does it check implicit override? (NotRequired)
    #

          <show>package</show>
        </configuration>
      </plugin>
      <!-- Disable "normal" testing, which doesn't work for GWT tests. -->
      <plugin>
        <artifactId>maven-surefire-plugin</artifactId>

### Download and Install/Run

Fess 15.0 is now available and can be downloaded on the [Releases page](https://github.com/codelibs/fess/releases "download"). Downloads come in 3 flavors: deb, rpm, zip.

The following commands show how to use the zip download:

    $ unzip fess-15.0.x.zip
    $ cd fess-15.0.x
    $ ./bin/fess

For more details, see the [Installation Guide](https://fess.codelibs.org/15.0/install/index.html).

### Docker

As you saw in the previous chapter about [Deployment Concepts](concepts.md){.internal-link target=_blank}, there are multiple strategies you can use.

Here I'll show you how to use **Uvicorn** with **worker processes** using the `fastapi` command or the `uvicorn` command directly.

/// info

---

"_I’m over the moon excited about **FastAPI**. It’s so fun!_"

<div style="text-align: right; margin-right: 10%;">Brian Okken - <strong><a href="https://pythonbytes.fm/episodes/show/123/time-to-right-the-py-wrongs?time_in_sec=855" target="_blank">Python Bytes</a> podcast host</strong> <a href="https://x.com/brianokken/status/1112220079972728832" target="_blank"><small>(ref)</small></a></div>

---

## Lifespan { #lifespan }

You can define this *startup* and *shutdown* logic using the `lifespan` parameter of the `FastAPI` app, and a "context manager" (I'll show you what that is in a second).

Let's start with an example and then see it in detail.

We create an async function `lifespan()` with `yield` like this:

{* ../../docs_src/events/tutorial003.py hl[16,19] *}