'a', "first",
            'z', "last");
    ArrayBasedEscaperMap fem = ArrayBasedEscaperMap.create(map);
    // Array length is highest character value + 1
    assertThat(fem.getReplacementArray()).hasLength('z' + 1);
  }

  public void testMapping() {
    Map<Character, String> map =
        ImmutableMap.of(
            '\0', "zero",
            'a', "first",
            'b', "second",
            'z', "last",

    assertThat(set.needsAllocArrays()).isTrue();
    assertThat(set.elements).isNull();

    set.add(1);
    assertThat(set.needsAllocArrays()).isFalse();
    assertThat(set.elements).hasLength(CompactHashing.DEFAULT_SIZE);
  }

  public void testAllocArraysExpectedSize() {
    for (int i = 0; i <= CompactHashing.DEFAULT_SIZE; i++) {
      CompactHashSet<Integer> set = CompactHashSet.createWithExpectedSize(i);

이제 이 `Annotated`에 더 많은 정보를 넣을 수 있으므로(이 경우에는 추가 검증), `Annotated` 안에 `Query`를 추가하고 `max_length` 매개변수를 `50`으로 설정합니다:

{* ../../docs_src/query_params_str_validations/tutorial002_an_py310.py hl[9] *}

기본값은 여전히 `None`이므로, 매개변수는 여전히 선택적입니다.

하지만 `Annotated` 안에 `Query(max_length=50)`를 넣음으로써, 이 값에 대해 **추가 검증**을 적용하고 최대 50자까지만 허용하도록 FastAPI에 알려줍니다. 😎

/// tip | 팁

                            {
                                "required": True,
                                "schema": {
                                    "title": "Foo",
                                    "minLength": 1,
                                    "type": "string",
                                },
                                "name": "foo",
                                "in": "query",
                            }

追加情報（この場合は追加のバリデーション）を入れられる `Annotated` ができたので、`Annotated` の中に `Query` を追加し、パラメータ `max_length` を `50` に設定します:

{* ../../docs_src/query_params_str_validations/tutorial002_an_py310.py hl[9] *}

デフォルト値は引き続き `None` なので、このパラメータは依然としてオプショナルです。

しかし、`Annotated` の中に `Query(max_length=50)` を入れることで、この値に **追加のバリデーション** をしたい、最大 50 文字にしたい、と FastAPI に伝えています。 😎

/// tip | 豆知識

    q: Annotated[str | None, Query(max_length=50)] = None,
):
    return {"message": "Hello World"}
```

instead of:

```python
# DO NOT DO THIS
@app.get("/items/{item_id}")
async def read_item(
    item_id: int = Path(ge=1, description="The item ID"),
    q: str | None = Query(default=None, max_length=50),
):
    return {"message": "Hello World"}
```

    LoadingCache<?, ?> cache = CacheBuilder.newBuilder().initialCapacity(5).build(identityLoader());
    LocalCache<?, ?> map = CacheTesting.toLocalCache(cache);

    assertThat(map.segments).hasLength(4);
    assertThat(map.segments[0].table.length()).isEqualTo(2);
    assertThat(map.segments[1].table.length()).isEqualTo(2);
    assertThat(map.segments[2].table.length()).isEqualTo(2);

    LoadingCache<?, ?> cache = CacheBuilder.newBuilder().initialCapacity(5).build(identityLoader());
    LocalCache<?, ?> map = CacheTesting.toLocalCache(cache);

    assertThat(map.segments).hasLength(4);
    assertThat(map.segments[0].table.length()).isEqualTo(2);
    assertThat(map.segments[1].table.length()).isEqualTo(2);
    assertThat(map.segments[2].table.length()).isEqualTo(2);

  }

  private enum LexicographicalComparator implements Comparator<byte[]> {
    INSTANCE;

    @Override
    public int compare(byte[] left, byte[] right) {
      int minLength = Math.min(left.length, right.length);
      for (int i = 0; i < minLength; i++) {
        int result = Byte.compare(left[i], right[i]);
        if (result != 0) {
          return result;
        }
      }
      return left.length - right.length;

* Update docs for first steps, links and rewording. PR [#1518](https://github.com/tiangolo/fastapi/pull/1518) by [@yankeexe](https://github.com/yankeexe).
* Enable `showCommonExtensions` in Swagger UI to show additional validations like `maxLength`, etc. PR [#1466](https://github.com/tiangolo/fastapi/pull/1466) by [@TiewKH](https://github.com/TiewKH).