}

    private void add(@Nullable Object[] elements, int n) {
      ensureRoomFor(n);
      /*
       * The following call is not statically checked, since arraycopy accepts plain Object for its
       * parameters. If it were statically checked, the checker would still be OK with it, since
       * we're copying into a `contents` array whose type allows it to contain nulls. Still, it's

    def __call__(self, q: str = ""):
        if q:
            return self.fixed_content in q
        return False


checker = FixedContentQueryChecker("bar")


@app.get("/query-checker/")
async def read_query_check(fixed_content_included: Annotated[bool, Depends(checker)]):

These custom validators are for things that can be checked with **only** the **same data** provided in the request.

///

### Understand that Code { #understand-that-code }

使用以下代码创建类实例：

{* ../../docs_src/dependencies/tutorial011.py hl[16] *}

这样就可以**参数化**依赖项，它包含 `checker.fixed_content` 的属性 - `"bar"`。

## 把实例作为依赖项

然后，不要再在 `Depends(checker)` 中使用 `Depends(FixedContentQueryChecker)`， 而是要使用 `checker`，因为依赖项是类实例 - `checker`，不是类。

处理依赖项时，**FastAPI** 以如下方式调用 `checker`：

```Python
checker(q="somequery")
```

……并用*路径操作函数*的参数 `fixed_content_included` 返回依赖项的值：

## Utilize a instância como dependência { #use-the-instance-as-a-dependency }

Então, nós podemos utilizar este `checker` em um `Depends(checker)`, no lugar de `Depends(FixedContentQueryChecker)`, porque a dependência é a instância, `checker`, e não a própria classe.

E quando a dependência for resolvida, o **FastAPI** chamará este `checker` como:

```Python
checker(q="somequery")

            for (String s : footer) {
                writer.writeln(s);
            }
        }
        writer.flush();
    }

    /**
     * Checks if parts of the passed in comment can be used as header comment.
     * This method checks whether a header comment can be defined (i.e. whether
     * this is the first comment in the loaded file). If this is the case, it is

            for (String s : footer) {
                writer.writeln(s);
            }
        }
        writer.flush();
    }

    /**
     * Checks if parts of the passed in comment can be used as header comment.
     * This method checks whether a header comment can be defined (i.e. whether
     * this is the first comment in the loaded file). If this is the case, it is

                String rawChildModelVersion = childModel.getVersion();

                if (rawChildModelVersion == null) {
                    // Message below is checked for in the MNG-2199 core IT.
                    problems.add(new ModelProblemCollectorRequest(Severity.FATAL, Version.V31)
                            .setMessage("Version must be a constant")

        this.logLevel = logLevel;
    }

    /**
     * Checks if the log level is DEBUG.
     *
     * @return true if DEBUG, false otherwise
     */
    public boolean isDebugEnabled() {
        return DEBUG.equals(logLevel);
    }

    /**
     * Checks if the log level is INFO.
     *
     * @return true if INFO, false otherwise
     */

    "path,expected_status,expected_response",
    [
        (
            "/query-checker/",
            200,
            {"fixed_content_in_query": False},
        ),
        (
            "/query-checker/?q=qwerty",
            200,
            {"fixed_content_in_query": False},
        ),
        (
            "/query-checker/?q=foobar",
            200,
            {"fixed_content_in_query": True},
        ),