## Eine Anwendung mit Callbacks

Sehen wir uns das alles anhand eines Beispiels an.

Stellen Sie sich vor, Sie entwickeln eine Anwendung, mit der Sie Rechnungen erstellen können.

Diese Rechnungen haben eine `id`, einen optionalen `title`, einen `customer` (Kunde) und ein `total` (Gesamtsumme).

 */

package com.google.common.collect.testing;

import com.google.common.annotations.GwtCompatible;
import java.util.Queue;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Creates queues, containing sample elements, to be tested.
 *
 * @author Jared Levy
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface TestQueueGenerator<E extends @Nullable Object> extends TestCollectionGenerator<E> {

* <a href="https://docs.porter.run/language-specific-guides/fastapi" class="external-link" target="_blank">Porter</a>

```JSON
{"item_id":"foo"}
```

## Pfad-Parameter mit Typen

Sie können den Typ eines Pfad-Parameters in der Argumentliste der Funktion deklarieren, mit Standard-Python-Typannotationen:

```Python hl_lines="7"
{!../../docs_src/path_params/tutorial002.py!}
```

 Mas quando o formulário inclui arquivos, ele é codificado como `multipart/form-data`. Você lerá sobre como lidar com arquivos no próximo capítulo.

 * a one-arg constructor accepting its inner generator as an argument. This requirement enables it
 * to generate source code (since GWT cannot use reflection to generate the suites).
 *
 * @author Chris Povirk
 */
@GwtCompatible
public interface DerivedGenerator {
  TestSubjectGenerator<?> getInnerGenerator();

 * a one-arg constructor accepting its inner generator as an argument. This requirement enables it
 * to generate source code (since GWT cannot use reflection to generate the suites).
 *
 * @author Chris Povirk
 */
@GwtCompatible
public interface DerivedGenerator {
  TestSubjectGenerator<?> getInnerGenerator();

  # Column 1 is left only, Column 2 is right only, Column 3 is shared lines
  # Select lines unique to actual_licenses, i.e. extra licenses.
  comm -1 -3 $BATS_TEST_TMPDIR/expected_licenses $BATS_TEST_TMPDIR/actual_licenses | grep -v -f $BATS_TEST_TMPDIR/allowed_to_be_extra > $BATS_TEST_TMPDIR/actual_extra_licenses || true
  # Select lines unique to expected_licenses, i.e. missing licenses

import static java.util.concurrent.TimeUnit.SECONDS;
import static org.junit.Assert.assertThrows;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import com.google.common.collect.Queues;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.SampleElements.Chars;
import java.util.List;

/**
 * Generates {@code List<Character>} instances for test suites.
 *
 * @author Kevin Bourrillion
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class TestCharacterListGenerator implements TestListGenerator<Character> {