## An app with callbacks { #an-app-with-callbacks }

Let's see all this with an example.

Imagine you develop an app that allows creating invoices.

These invoices will have an `id`, `title` (optional), `customer`, and `total`.

The user of your API (an external developer) will create an invoice in your API with a POST request.

Then your API will (let's imagine):

### 2. Warning

**Community Impact**: A violation through a single incident or series
of actions.

**Consequence**: A warning with consequences for continued behavior. No
interaction with the people involved, including unsolicited interaction with
those enforcing the Code of Conduct, for a specified period. This
includes avoiding interactions in community spaces and external channels

    // ThreadLocal is not available to GWT, so we always reuse the same
    // instance.  It is always safe to return the same instance because
    // javascript is single-threaded, and only used by blocks that doesn't
    // involve async callbacks.
    return CHAR_BUFFER;
  }

  private Platform() {}

👉 💼, ⚫️ `str`:

```Python
"{$callback_url}/invoices/{$request.body.id}"
```

, 🚥 👆 🛠️ 👩‍💻 (🔢 👩‍💻) 📨 📨 *👆 🛠️* :

```
https://yourapi.com/invoices/?callback_url=https://www.external.org/events
```

⏮️ 🎻 💪:

```JSON
{
    "id": "2expen51ve",
    "customer": "Mr. Richie Rich",

Nesse caso, é a `str`:

```Python
"{$callback_url}/invoices/{$request.body.id}"
```

Então, se o usuário da sua API (o desenvolvedor externo) enviar uma solicitação para *sua API* para:

```
https://yourapi.com/invoices/?callback_url=https://www.external.org/events
```

com um corpo JSON de:

```JSON
{
    "id": "2expen51ve",

En este caso, es el `str`:

```Python
"{$callback_url}/invoices/{$request.body.id}"
```

Entonces, si el usuario de tu API (el desarrollador externo) envía un request a *tu API* a:

```
https://yourapi.com/invoices/?callback_url=https://www.external.org/events
```

con un JSON body de:

```JSON
{
    "id": "2expen51ve",

In diesem Fall ist es der `str`:

```Python
"{$callback_url}/invoices/{$request.body.id}"
```

Wenn Ihr API-Benutzer (der externe Entwickler) also einen Request an *Ihre API* sendet, via:

```
https://yourapi.com/invoices/?callback_url=https://www.external.org/events
```

mit einem JSON-Körper:

```JSON
{
    "id": "2expen51ve",

    @Mock
    private Request<CommonServerMessageBlockResponse> request;

    @Mock
    private CommonServerMessageBlockResponse response;

    @Test
    @DisplayName("connectLogon invokes underlying implementation")
    void connectLogon_invocation_isForwarded() throws Exception {
        // Act
        tree.connectLogon(context);

        // Assert - verify interaction with dependency

        String actualString = request.toString();

        assertTrue(actualString.startsWith(expectedStringPrefix));
        assertTrue(actualString.endsWith("]"));
        // Further verification could involve mocking super.toString() if needed
    }

   *     annotation type, rather than an interface
   */
  <T> T newProxy(T target, Class<T> interfaceType, long timeoutDuration, TimeUnit timeoutUnit);

  /**
   * Invokes a specified Callable, timing out after the specified time limit. If the target method
   * call finishes before the limit is reached, the return value or a wrapped exception is