if (existingCounter.compareAndSet(oldValue, newValue)) {
          if (newValue == 0) {
            // Just CASed to 0; remove the entry to clean up the map. If the removal fails,
            // another thread has already replaced it with a new counter, which is fine.
            countMap.remove(element, existingCounter);
          }
          return oldValue;
        }
      } else {
        return 0;
      }
    }

          nanos -= System.nanoTime() - now; // subtract the actual time we waited
        }
      }
    }
  }

  /**
   * Checks if the executor has been shut down and increments the running task count.
   *
   * @throws RejectedExecutionException if the executor has been previously shutdown
   */
  private void startTask() {
    synchronized (lock) {
      if (shutdown) {

  initialDelaySeconds: 120
  periodSeconds: 15
  timeoutSeconds: 10
  successThreshold: 1
  failureThreshold: 3
```

## Cluster probe

### Cluster-writeable probe

The reply is '200 OK' if cluster has write quorum if not it returns '503 Service Unavailable'.

```
curl http://minio1:9001/minio/health/cluster
HTTP/1.1 503 Service Unavailable
Accept-Ranges: bytes
Content-Length: 0
Server: MinIO
Vary: Origin

      /*
       * requireNonNull is safe because:
       *
       * - This is a TrustedFuture, so tryInternalFastPathGetFailure will in fact return the failure
       *   cause if this Future has failed.
       *
       * - And this future *has* failed: This method is called only from handleException (through
       *   getOrInitSeenExceptions). handleException tried to call setException and failed, so

              try {
                if (state() != State.STOPPING) {
                  // This means that the state has changed since we were scheduled. This implies
                  // that an execution of runOneIteration has thrown an exception and we have
                  // transitioned to a failed state, also this means that shutDown has already
                  // been called, so we do not want to call it again.
                  return;

```
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

Let's say that now the file `main.py` with your **FastAPI** app has some other **path operations**.

It has a `GET` operation that could return an error.

It has a `POST` operation that could return several errors.

Both *path operations* require an `X-Token` header.

{* ../../docs_src/app_testing/app_b_an_py310/main.py *}

Ayrıca sayısal doğrulamalar da tanımlayabilirsiniz:

* `gt`: `g`reater `t`han
* `ge`: `g`reater than or `e`qual
* `lt`: `l`ess `t`han
* `le`: `l`ess than or `e`qual

/// info | Bilgi

`Query`, `Path` ve ileride göreceğiniz diğer class'lar ortak bir `Param` class'ının alt class'larıdır.

  // The keys of this map are all the active sessions using this graph. Each
  // value records whether the graph has been mutated since the corresponding
  // session has been run (this is detected in RecordMutation function). If the
  // string is empty, no mutation has occurred. Otherwise the string is a
  // description of the mutation suitable for returning to the user.
  //

* The **database model** would probably need to have a hashed password.

/// danger

Never store user's plaintext passwords. Always store a "secure hash" that you can then verify.

If you don't know, you will learn what a "password hash" is in the [security chapters](security/simple-oauth2.md#password-hashing).

///

## Multiple models { #multiple-models }

   * {@code null}!) before returning it to callers. Depending on how the code is structured, a
   * nullness analysis might not understand that the field has been populated. To avoid that problem
   * without having to add {@code @SuppressWarnings}, the code can call this method.
   *
   * <p>Why <i>not</i> just add {@code SuppressWarnings}? The problem is that this method is