catcher.getEvents());
    }
  }

  public void testToString() throws Exception {
    EventBus eventBus = new EventBus("a b ; - \" < > / \\ €");
    assertEquals("EventBus{a b ; - \" < > / \\ €}", eventBus.toString());
  }

  /**
   * Tests that bridge methods are not subscribed to events. In Java 8, annotations are included on

    private final EventBus eventBus = new EventBus();

    @Subscribe
    public void handle(@Nullable Object unused) {}

    Subscriber toSubscriber() throws Exception {
      return Subscriber.create(eventBus, this, subscriberMethod());
    }

    SubscriberExceptionContext toContext() {
      return new SubscriberExceptionContext(eventBus, new Object(), this, subscriberMethod());
    }

   */
  private final ConcurrentMap<Class<?>, CopyOnWriteArraySet<Subscriber>> subscribers =
      Maps.newConcurrentMap();

  /** The event bus this registry belongs to. */
  @Weak private final EventBus bus;

  SubscriberRegistry(EventBus bus) {
    this.bus = checkNotNull(bus);
  }

  /** Registers all subscriber methods on the given listener object. */
  void register(Object listener) {

 * the License.
 */

package com.google.common.eventbus;

import static com.google.common.base.Preconditions.checkNotNull;
import static java.util.Objects.requireNonNull;

import com.google.common.collect.Queues;
import java.util.Iterator;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;

/**
 * Handler for dispatching events to subscribers, providing different event ordering guarantees that

      options:
        - com.google.common.annotations
        - com.google.common.base
        - com.google.common.cache
        - com.google.common.collect
        - com.google.common.escape
        - com.google.common.eventbus
        - com.google.common.graph
        - com.google.common.hash
        - com.google.common.io
        - com.google.common.math
        - com.google.common.net
        - com.google.common.primitives

  private static final ImmutableSet<String> GUAVA_PACKAGES =
      FluentIterable.of(
              "base",
              "cache",
              "collect",
              "escape",
              "eventbus",
              "graph",
              "hash",
              "html",
              "io",
              "math",
              "net",
              "primitives",
              "reflect",

  private static final ImmutableSet<String> GUAVA_PACKAGES =
      FluentIterable.of(
              "base",
              "cache",
              "collect",
              "escape",
              "eventbus",
              "graph",
              "hash",
              "html",
              "io",
              "math",
              "net",
              "primitives",
              "reflect",

        - com.google.common.annotations
        - com.google.common.base
        - com.google.common.cache
        - com.google.common.collect
        - com.google.common.escape
        - com.google.common.eventbus
        - com.google.common.graph
        - com.google.common.hash
        - com.google.common.io
        - com.google.common.math
        - com.google.common.net
        - com.google.common.primitives

```Python hl_lines="22"
{!../../docs_src/events/tutorial003.py!}
```

## Eventos alternativos (deprecados)

/// warning | "Aviso"

A maneira recomendada para lidar com a *inicialização* e o *encerramento* é usando o parâmetro `lifespan` da aplicação `FastAPI` como descrito acima.

使用 `startup` 事件声明 `app` 启动前运行的函数：

```Python hl_lines="8"
{!../../docs_src/events/tutorial001.py!}
```

本例中，`startup` 事件处理器函数为项目数据库（只是**字典**）提供了一些初始值。

**FastAPI** 支持多个事件处理器函数。

只有所有 `startup` 事件处理器运行完毕，**FastAPI** 应用才开始接收请求。

## `shutdown` 事件

使用 `shutdown` 事件声明 `app` 关闭时运行的函数：

```Python hl_lines="6"
{!../../docs_src/events/tutorial002.py!}
```