or even industries — utilities useful for a sizable proportion of all Java programmers
        everywhere. If you can give enough detail such that any of us can imagine coming across
        a similar need in our own work, that's extremely helpful in studying how broadly useful the
        feature will be.

  - type: textarea
    attributes:
      label: Concrete Use Cases

 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible
public class ListenableFutureTask<V extends @Nullable Object> extends FutureTask<V>
    implements ListenableFuture<V> {
  // TODO(cpovirk): explore ways of making ListenableFutureTask final. There are some valid reasons
  // such as BoundedQueueExecutorService to allow extends but it would be nice to make it final to
  // avoid unintended usage.

  + Clearly describe the issue, including steps to reproduce when it is a bug.
  + Make sure you fill in the earliest version that you know has the issue.
+ Fork the repository on GitHub.

Making and Submitting Changes
--------------

We accept Pull Requests via GitHub. The [developer mailing list][dev-ml-list] is the
main channel of communication for contributors.  

## 附加的服务器

/// warning | 警告

此用例较难，可以跳过。

///

默认情况下，**FastAPI** 使用 `root_path` 的链接在 OpenAPI 概图中创建 `server`。

但也可以使用其它备选 `servers`，例如，需要同一个 API 文档与 staging 和生产环境交互。

如果传递自定义 `servers` 列表，并有 `root_path`（ 因为 API 使用了代理），**FastAPI** 会在列表开头使用这个 `root_path` 插入**服务器**。

例如：

{* ../../docs_src/behind_a_proxy/tutorial003.py hl[4:7] *}

这段代码生产如下 OpenAPI 概图：

Sie können aber auch andere alternative `server` bereitstellen, beispielsweise wenn Sie möchten, dass *dieselbe* Dokumentationsoberfläche mit einer Staging- und Produktionsumgebung interagiert.

Events
======

Events allow you to capture metrics on your application’s HTTP calls. Use events to monitor:

 * The size and frequency of the HTTP calls your application makes. If you’re making too many calls, or your calls are too large, you should know about it!
 * The performance of these calls on the underlying network. If the network’s performance isn’t sufficient, you need to either improve the network or use less of it.

### EventListener

        }
    }

    // Test environment title variations
    public void xtest_environmentTitleVariations() {
        String[] titles = { "Local Development", "Integration Test", "Staging Environment", "Production", "災害復旧環境" };

        for (String title : titles) {
            FessEnv.SimpleImpl titleEnv = new FessEnv.SimpleImpl() {
                protected Properties prepareProperties() {

## Um aplicativo com callbacks

Vamos ver tudo isso com um exemplo.

Imagine que você tem um aplicativo que permite criar faturas.

Essas faturas terão um `id`, `title` (opcional), `customer` e `total`.

O usuário da sua API (um desenvolvedor externo) criará uma fatura em sua API com uma solicitação POST.

{* ../../docs_src/query_params_str_validations/tutorial007.py hl[10] *}

E uma `description`:

{* ../../docs_src/query_params_str_validations/tutorial008.py hl[13] *}

## Apelidos (alias) de parâmetros

Imagine que você queira que um parâmetro tenha o nome `item-query`.

Desta maneira:

```
http://127.0.0.1:8000/items/?item-query=foobaritems
```

Mas o nome `item-query` não é um nome de váriavel válido no Python.

# Security - First Steps { #security-first-steps }

Let's imagine that you have your **backend** API in some domain.

And you have a **frontend** in another domain or in a different path of the same domain (or in a mobile application).

And you want to have a way for the frontend to authenticate with the backend, using a **username** and **password**.

We can use **OAuth2** to build that with **FastAPI**.