* graph with an edge connecting node A to node B if node B is {@link #reachableNodes(Graph,
   * Object) reachable} from node A.
   *
   * <p>This is a "snapshot" based on the current topology of {@code graph}, rather than a live view
   * of the transitive closure of {@code graph}. In other words, the returned {@link Graph} will not
   * be updated after modifications to {@code graph}.
   *

   * graph with an edge connecting node A to node B if node B is {@link #reachableNodes(Graph,
   * Object) reachable} from node A.
   *
   * <p>This is a "snapshot" based on the current topology of {@code graph}, rather than a live view
   * of the transitive closure of {@code graph}. In other words, the returned {@link Graph} will not
   * be updated after modifications to {@code graph}.
   *

# Erste Schritte

Die einfachste FastAPI-Datei könnte wie folgt aussehen:

{* ../../docs_src/first_steps/tutorial001.py *}

Kopieren Sie dies in eine Datei `main.py`.

Starten Sie den Live-Server:

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)

# 第一步

最簡單的 FastAPI 檔案可能看起來像這樣：

{* ../../docs_src/first_steps/tutorial001.py *}

將其複製到一個名為 `main.py` 的文件中。

執行即時重新載入伺服器（live server）：

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:single">main.py</u>
<font color="#3465A4">INFO    </font> Using path <font color="#3465A4">main.py</font>

 * imposes both obligations and limits on the client application.
 *
 * ### The response body must be closed.
 *
 * Each response body is backed by a limited resource like a socket (live network responses) or
 * an open file (for cached responses). Failing to close the response body will leak resources and
 * may ultimately cause the application to slow down or crash.
 *

    private const val FILE_HEADER_SIZE = 32L

    /**
     * Creates a new relay that reads a live stream from [upstream], using [file] to share that data
     * with other sources.
     *
     * **Warning:** callers to this method must immediately call [newSource] to create a source and
     * close that when they're done. Otherwise a handle to [file] will be leaked.
     */
    @Throws(IOException::class)

    return capacityWithoutIt >= addressState.policy.minimumConcurrentCalls
  }

  /**
   * Prunes any leaked calls and then returns the number of remaining live calls on [connection].
   * Calls are leaked if the connection is tracking them but the application code has abandoned
   * them. Leak detection is imprecise and relies on garbage collection.
   */

import java.util.regex.Pattern;
import junit.framework.AssertionFailedError;
import junit.framework.TestCase;
import org.jspecify.annotations.Nullable;

/**
 * Tests for {@link ForwardingWrapperTester}. Live in a different package to detect reflection
 * access issues, if any.
 *
 * @author Ben Yu
 */
public class ForwardingWrapperTesterTest extends TestCase {

Remember how our app/file structure looks like:

<img src="/img/tutorial/bigger-applications/package.drawio.svg">

---

The two dots `..`, like in:

```Python
from ..dependencies import get_token_header
```

mean:

* Starting in the same package that this module (the file `app/routers/items.py`) lives in (the directory `app/routers/`)...

   */
  public long sum() {
    return map.values().stream().mapToLong(Long::longValue).sum();
  }

  @LazyInit private transient @Nullable Map<K, Long> asMap;

  /** Returns a live, read-only view of the map backing this {@code AtomicLongMap}. */
  public Map<K, Long> asMap() {
    Map<K, Long> result = asMap;
    return (result == null) ? asMap = createAsMap() : result;
  }