# Clase personalizada de Request y APIRoute { #custom-request-and-apiroute-class }

En algunos casos, puede que quieras sobrescribir la lógica utilizada por las clases `Request` y `APIRoute`.

En particular, esta puede ser una buena alternativa a la lógica en un middleware.

Por ejemplo, si quieres leer o manipular el request body antes de que sea procesado por tu aplicación.

/// danger | Advertencia

Esta es una funcionalidad "avanzada".

The **default** value of the **function parameter** is the **actual default** value, that's more intuitive with Python in general. 😌

 */
@SuppressWarnings("JdkObsolete")
public abstract class ForwardingSortedMap<K extends @Nullable Object, V extends @Nullable Object>
    extends ForwardingMap<K, V> implements SortedMap<K, V> {
  // TODO(lowasser): identify places where thread safety is actually lost

  /** Constructor for use by subclasses. */
  protected ForwardingSortedMap() {}

  @Override
  protected abstract SortedMap<K, V> delegate();

  @Override

 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible
public abstract class ForwardingList<E extends @Nullable Object> extends ForwardingCollection<E>
    implements List<E> {
  // TODO(lowasser): identify places where thread safety is actually lost

  /** Constructor for use by subclasses. */
  protected ForwardingList() {}

  @Override
  protected abstract List<E> delegate();

  @Override

### Otras funciones de utilidad { #other-utility-functions }

Cualquier otra función de utilidad que llames directamente puede ser creada con `def` normal o `async def` y FastAPI no afectará la forma en que la llames.

Esto contrasta con las funciones que FastAPI llama por ti: *path operation functions* y dependencias.

 * @since 2.0
 */
@GwtCompatible
public class Joiner {
  /** Returns a joiner which automatically places {@code separator} between consecutive elements. */
  public static Joiner on(String separator) {
    return new Joiner(separator);
  }

  /** Returns a joiner which automatically places {@code separator} between consecutive elements. */
  public static Joiner on(char separator) {

It can't handle nested models very well. So, if the JSON body in the request is a JSON object that has inner fields that in turn are nested JSON objects, it cannot be properly documented and validated.

 * from uniform), and amortized since some operations can trigger a hash table resize.
 *
 * <p>As compared with {@link java.util.LinkedHashMap}, this structure places significantly reduced
 * load on the garbage collector by only using a constant number of internal objects.
 *
 * <p>This class should not be assumed to be universally superior to {@code

///

## Multiple models { #multiple-models }

Here's a general idea of how the models could look like with their password fields and the places where they are used:

{* ../../docs_src/extra_models/tutorial001_py310.py hl[7,9,14,20,22,27:28,31:33,38:39] *}

### About `**user_in.model_dump()` { #about-user-in-model-dump }

   * it is returned directly. Otherwise, a new array of size {@code minLength + padding} is
   * returned, containing the values of {@code array}, and zeroes in the remaining places.
   *
   * @param array the source array
   * @param minLength the minimum length the returned array must guarantee
   * @param padding an extra amount to "grow" the array by if growth is necessary