// The maximum allowed number of concurrent Send() calls to all configured notifications targets
	maxConcurrentAsyncSend = 50000
)

// Target - event target interface
type Target interface {
	ID() TargetID
	IsActive() (bool, error)
	Save(Event) error
	SendFromStore(store.Key) error
	Close() error
	Store() TargetStore
}

// TargetStore is a shallow version of a target.Store
type TargetStore interface {
	Len() int
}

}
```

### 未激活用户

测试未激活用户，输入以下信息，进行身份验证：

用户名：`alice`

密码：`secret2`

然后，执行 `/users/me` 路径的 `GET` 操作。

显示下列**未激活用户**错误信息：

```JSON
{
  "detail": "Inactive user"
}
```

## 小结

使用本章的工具实现基于 `username` 和 `password` 的完整 API 安全系统。

这些工具让安全系统兼容任何数据库、用户及数据模型。

唯一欠缺的是，它仍然不是真的**安全**。

   * {@code A -> B}.
   *
   * @since 9.0 (in 1.0 as {@code com.google.common.base.Service.State})
   */
  enum State {
    /** A service in this state is inactive. It does minimal work and consumes minimal resources. */
    NEW,

    /** A service in this state is transitioning to {@link #RUNNING}. */
    STARTING,

    /** A service in this state is operational. */

Y para comunicarte usando WebSockets con tu backend probablemente usarías las utilidades de tu frontend.

O podrías tener una aplicación móvil nativa que se comunica con tu backend de WebSocket directamente, en código nativo.

O podrías tener alguna otra forma de comunicarte con el endpoint de WebSocket.

---

Pero para este ejemplo, usaremos un documento HTML muy simple con algo de JavaScript, todo dentro de un string largo.

        });
    }

    /**
     * Deletes all crawling sessions and their parameters except for the specified active sessions.
     * This is a cleanup operation that removes inactive session data while preserving active ones.
     *
     * @param activeSessionId a set of session IDs to preserve during the cleanup operation
     */
    public void deleteOldSessions(final Set<String> activeSessionId) {

   * instance that is ready to receive data. Example:
   *
   * {@snippet :
   * HashFunction hf = Hashing.md5();
   * HashCode hc = hf.newHasher()
   *     .putLong(id)
   *     .putBoolean(isActive)
   *     .hash();
   * }
   */
  Hasher newHasher();

  /**
   * Begins a new hash code computation as {@link #newHasher()}, but provides a hint of the expected

   * instance that is ready to receive data. Example:
   *
   * {@snippet :
   * HashFunction hf = Hashing.md5();
   * HashCode hc = hf.newHasher()
   *     .putLong(id)
   *     .putBoolean(isActive)
   *     .hash();
   * }
   */
  Hasher newHasher();

  /**
   * Begins a new hash code computation as {@link #newHasher()}, but provides a hint of the expected

		if tgts[target.ID().ID] {
			// When target set should be online
			yes, err := target.IsActive()
			if err == nil && !yes {
				err = ErrTargetsOffline
			}
			if err != nil {
				return fmt.Errorf("error (%s): %w", target.ID(), err)
			}
		} else {
			// Just for call init.
			// Ignore target is online or offline
			_, _ = target.IsActive()
		}
	}

	return nil
}

    assertThat(notification).isEqualTo(immutableEntry(key, value2));
    assertThat(notification.getCause()).isEqualTo(RemovalCause.REPLACED);
    assertThat(listener.isEmpty()).isTrue();

    // inactive
    Object value3 = new Object();
    map.clear();
    listener.clear();
    assertThat(segment.count).isEqualTo(0);
    table.set(index, entry);

    assertThat(notification).isEqualTo(immutableEntry(key, value2));
    assertThat(notification.getCause()).isEqualTo(RemovalCause.REPLACED);
    assertThat(listener.isEmpty()).isTrue();

    // inactive
    Object value3 = new Object();
    map.clear();
    listener.clear();
    assertThat(segment.count).isEqualTo(0);
    table.set(index, entry);