// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package bpool

import "sync"

// Pool is a single type sync.Pool with a few extra properties:
// If New is not set Get may return the zero value of T.
type Pool[T any] struct {
	New func() T
	p   sync.Pool
}

// Get will retuen a new T
func (p *Pool[T]) Get() T {
	v, ok := p.p.Get().(T)

        public Map<String, String> extraInterpolationSource() {
            Map<String, String> extra = new HashMap<>();
            extra.put("session.topDirectory", topDirectory.toString());
            if (rootDirectory != null) {
                extra.put("session.rootDirectory", rootDirectory.toString());
            }
            return extra;
        }
    }

    @Override

Dado que `Annotated` puede tener más de una anotación de metadato, ahora podrías incluso usar la misma función con otras herramientas, como <a href="https://typer.tiangolo.com/" class="external-link" target="_blank">Typer</a>. 🚀

## Agregar más validaciones { #add-more-validations }

También puedes agregar un parámetro `min_length`:

     * Buffer type for device information.
     */
    int DEVICE_INFO_TYPE = 0xE;
    /**
     * Buffer type for device claims information.
     */
    int DEVICE_CLAIMS_TYPE = 0xF;

    /**
     * Flag for extra SIDs in logon information.
     */
    int LOGON_EXTRA_SIDS = 0x20;
    /**
     * Flag for resource groups in logon information.
     */
    int LOGON_RESOURCE_GROUPS = 0x200;

    /**

      builder.append(args[i++]);
      templateStart = placeholderStart + 2;
    }
    builder.append(template.substring(templateStart));

    // if we run out of placeholders, append the extra args in square braces
    if (i < args.length) {
      builder.append(" [");
      builder.append(args[i++]);
      while (i < args.length) {
        builder.append(", ");
        builder.append(args[i++]);
      }

```json
{
    "detail": [
        {
            "type": "extra_forbidden",
            "loc": ["header", "tool"],
            "msg": "Extra inputs are not permitted",
            "input": "plumbus",
        }
    ]
}
```

## Підсумок

from typing import Annotated

from fastapi import Cookie, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Cookies(BaseModel):
    model_config = {"extra": "forbid"}

    session_id: str
    fatebook_tracker: str | None = None
    googall_tracker: str | None = None


@app.get("/items/")
async def read_items(cookies: Annotated[Cookies, Cookie()]):

Pydanticのモデルの Configuration を利用して、 `extra` フィールドを `forbid` とすることができます。

{* ../../docs_src/cookie_param_models/tutorial002_an_py39.py hl[10] *}

もしクライアントが**余分なクッキー**を送ろうとすると、**エラー**レスポンスが返されます。

from typing import Annotated, Union

from fastapi import Cookie, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Cookies(BaseModel):
    model_config = {"extra": "forbid"}

    session_id: str
    fatebook_tracker: Union[str, None] = None
    googall_tracker: Union[str, None] = None


@app.get("/items/")
async def read_items(cookies: Annotated[Cookies, Cookie()]):

 * annotation implies nothing about the quality or performance of the API in question, only the fact
 * that it is not "API-frozen."
 *
 * <p>It is generally safe for <i>applications</i> to depend on beta APIs, at the cost of some extra
 * work during upgrades. However it is generally inadvisable for <i>libraries</i> (which get
 * included on users' CLASSPATHs, outside the library developers' control) to do so.
 *
 * @author Kevin Bourrillion
 */