* single Object array, do not get any special handling; their hash codes are based on identity
   * and not contents.
   *
   * <p>This is useful for implementing {@link Object#hashCode()}. For example, in an object that
   * has three properties, {@code x}, {@code y}, and {@code z}, one could write:
   *
   * {@snippet :
   * public int hashCode() {
   *   return Objects.hashCode(getX(), getY(), getZ());
   * }

   * the source or written to the sink. Typically, this will just return the input directly, but in
   * some cases it may alter the input. For example, if the factory returns a sliced view of a
   * source created with some given bytes, this method would return a subsequence of the given
   * (byte[]) data.
   */
  T getExpected(T data);

It might also help avoid confusion for new developers that see an unused parameter in your code and could think it's unnecessary.

///

/// info

In this example we use invented custom headers `X-Key` and `X-Token`.

But in real cases, when implementing security, you would get more benefits from using the integrated [Security utilities (the next chapter)](../security/index.md).

///

* Enforce security, authentication, role requirements, etc.
* And many other things...

All these, while minimizing code repetition.

## First Steps { #first-steps }

Let's see a very simple example. It will be so simple that it is not very useful, for now.

But this way we can focus on how the **Dependency Injection** system works.

### Create a dependency, or "dependable" { #create-a-dependency-or-dependable }

## An app with callbacks { #an-app-with-callbacks }

Let's see all this with an example.

Imagine you develop an app that allows creating invoices.

These invoices will have an `id`, `title` (optional), `customer`, and `total`.

 * JavaScript parser `urltestparser.js` with which this class attempts to be compatible.
 *
 * Each line of the `urltestdata.txt` file specifies a test. Lines look like this:
 *
 * ```
 * http://example\t.\norg http://example.org/foo/bar s:http h:example.org p:/
 * ```
 */
class WebPlatformUrlTestData {
  var input: String? = null
  var base: String? = null
  var scheme = ""
  var username = ""
  var password: String? = null

distributors to deny you these rights or to ask you to surrender these
rights.  These restrictions translate to certain responsibilities for
you if you distribute copies of the library or if you modify it.

  For example, if you distribute copies of the library, whether gratis
or for a fee, you must give the recipients all the rights that we gave
you.  You must make sure that they, too, receive or can get the source

   * java.util.stream} Javadoc), that order is preserved, but entries are <a
   * href="ImmutableMultimap.html#iteration">grouped by key</a>.
   *
   * <p>Example:
   *
   * {@snippet :
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")

* `Decimal`：
    * 標準的 Python `Decimal`。
    * 在請求與回應中，與 `float` 的處理方式相同。
* 你可以在此查閱所有可用的 Pydantic 資料型別：[Pydantic 資料型別](https://docs.pydantic.dev/latest/usage/types/types/)。

## 範例 { #example }

以下是一個帶有參數、使用上述部分型別的 *路徑操作 (path operation)* 範例。

{* ../../docs_src/extra_data_types/tutorial001_an_py310.py hl[1,3,12:16] *}

請注意，函式內的參數會是它們的自然資料型別，因此你可以進行一般的日期運算，例如：

* `Decimal`:
    * 标准的 Python `Decimal`。
    * 在请求和响应中被当做 `float` 一样处理。
* 您可以在这里检查所有有效的 Pydantic 数据类型: [Pydantic data types](https://docs.pydantic.dev/latest/usage/types/types/)。

## 例子 { #example }

下面是一个*路径操作*的示例，其中的参数使用了上面的一些类型。

{* ../../docs_src/extra_data_types/tutorial001_an_py310.py hl[1,3,12:16] *}

注意，函数内的参数有原生的数据类型，你可以，例如，执行正常的日期操作，如: