{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[7:11,34:51] *}

/// tip

The `callback_url` query parameter uses a Pydantic [Url](https://docs.pydantic.dev/latest/api/networks/) type.

///

The only new thing is the `callbacks=invoices_callback_router.routes` as an argument to the *path operation decorator*. We'll see what that is next.

## Documenting the callback { #documenting-the-callback }

        if (notReallyReleased.isEmpty() == false) {
            throw new IllegalStateException(
                "out-of-date released versions"
                    + "\nFollowing versions are not really released, but the build thinks they are: "
                    + notReallyReleased
            );
        }

        Set<Version> incorrectlyConsideredUnreleased = new HashSet<>(authoritativeReleasedVersions);

[ Pydantic の詳細はドキュメントを参照してください](https://docs.pydantic.dev/)。

///

**FastAPI** はすべて Pydantic をベースにしています。

すべてのことは [チュートリアル - ユーザーガイド](tutorial/index.md) で実際に見ることができます。

## メタデータアノテーション付き型ヒント { #type-hints-with-metadata-annotations }

Python には、`Annotated` を使って型ヒントに **追加の <dfn title="データに関するデータ。この場合は型に関する情報（例えば説明）。">メタデータ</dfn>** を付与できる機能もあります。

`Annotated` は `typing` からインポートできます。

        statusLine.code == HTTP_CONTINUE -> {
          state = STATE_READ_RESPONSE_HEADERS
          responseBuilder
        }

        statusLine.code in (102 until 200) -> {
          // Processing and Early Hints will mean a second headers are coming.
          // Treat others the same for now
          state = STATE_READ_RESPONSE_HEADERS
          responseBuilder
        }

        else -> {

  private final long totalLoadTime;

  private final long evictionCount;

  /**
   * Constructs a new {@code CacheStats} instance.
   *
   * <p>Five parameters of the same type in a row is a bad thing, but this class is not constructed
   * by end users and is too fine-grained for a builder.
   */
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  public CacheStats(
      long hitCount,

  private final long totalLoadTime;

  private final long evictionCount;

  /**
   * Constructs a new {@code CacheStats} instance.
   *
   * <p>Five parameters of the same type in a row is a bad thing, but this class is not constructed
   * by end users and is too fine-grained for a builder.
   */
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  public CacheStats(
      long hitCount,

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 *     return myServer;
 *   }
 *
 *   @Override
 *   public void close() throws IOException {
 *     serverSocket.close();
 *   }
 * }
 * }
 *
 * <p id="cleaner">Here is how you might achieve the same thing using {@link java.lang.ref.Cleaner
 * Cleaner}, if you are using a Java version where that is available:
 *
 * {@snippet :
 * public class MyServer implements Closeable {

     *            dominant data.
     * @param hints A set of key-value pairs that customized merger implementations can use to carry domain-specific
     *            information along, may be <code>null</code>.
     */
    public void merge(Model target, Model source, boolean sourceDominant, Map<?, ?> hints) {
        Objects.requireNonNull(target, "target cannot be null");

 *     return myServer;
 *   }
 *
 *   @Override
 *   public void close() throws IOException {
 *     serverSocket.close();
 *   }
 * }
 * }
 *
 * <p id="cleaner">Here is how you might achieve the same thing using {@link java.lang.ref.Cleaner
 * Cleaner}, if you are using a Java version where that is available:
 *
 * {@snippet :
 * public class MyServer implements Closeable {