* the {@link EventBus}.
 *
 * <p>Unless also annotated with @{@link AllowConcurrentEvents}, event subscriber methods will be
 * invoked serially by each event bus that they are registered with.
 *
 * @author Cliff Biffle
 * @since 10.0
 */
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@Keep

			default:
			}
		}
	}
}

// Subscribe - Adds a subscriber to pubsub system
func (ps *PubSub[T, M]) Subscribe(mask M, subCh chan T, doneCh <-chan struct{}, filter func(entry T) bool) error {
	totalSubs := atomic.AddInt32(&ps.numSubscribers, 1)
	if ps.maxSubscribers > 0 && totalSubs > ps.maxSubscribers {
		atomic.AddInt32(&ps.numSubscribers, -1)
		return fmt.Errorf("the limit of `%d` subscribers is reached", ps.maxSubscribers)
	}
	ps.Lock()

	defer close(doneCh)
	if err := ps.Subscribe(MaskAll, ch1, doneCh, nil); err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if err := ps.Subscribe(MaskAll, ch2, doneCh, nil); err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	ps.Lock()
	defer ps.Unlock()

	if len(ps.subs) != 2 || ps.NumSubscribers(MaskAll) != 2 || ps.Subscribers() != 2 {
		t.Fatalf("expected 2 subscribers")
	}
}

  <url>http://www.apache.org/</url>

  <mailingLists>
    <mailingList>
      <name>parent</name>
      <post>******@****.***</post>
      <subscribe>subscribe@mailing.list.com</subscribe>
      <unsubscribe>unsubscribe@mailing.list.com</unsubscribe>
    </mailingList>
  </mailingLists>

  <build>
    <plugins>
      <plugin>
        <groupId>inheritance.configuration</groupId>

      <name>Maven User List</name>
      <subscribe>users-subscribe@maven.apache.org</subscribe>
      <unsubscribe>users-unsubscribe@maven.apache.org</unsubscribe>
      <post>******@****.***</post>
      <archive>http://mail-archives.apache.org/mod_mbox/maven-users</archive>
    </mailingList>
    <mailingList>
      <name>Maven Developer List</name>
      <subscribe>dev-subscribe@maven.apache.org</subscribe>

    boolean ready = true;
    final List<Object> eventsReceived = new ArrayList<>();

    @Subscribe
    public void listenForStrings(String event) {
      eventsReceived.add(event);
      ready = false;
      try {
        bus.post(SECOND);
      } finally {
        ready = true;
      }
    }

    @Subscribe
    public void listenForDoubles(Double event) {

  <url>http://www.apache.org/child/</url><!-- child's artifactId appended to parent url -->

  <mailingLists>
    <mailingList>
      <name>parent</name>
      <subscribe>subscribe@mailing.list.com</subscribe>
      <unsubscribe>unsubscribe@mailing.list.com</unsubscribe>
      <post>******@****.***</post>
    </mailingList>
  </mailingLists>

  <build>
    <plugins>
      <plugin>

    <!--mailingList> MNG-3124: no way to add a list to parent content, only full override
      <name>child</name>
      <post>******@****.***</post>
      <subscribe>subscribe@mailing.list.com</subscribe>
      <unsubscribe>unsubscribe@mailing.list.com</unsubscribe>
    </mailingList-->
  </mailingLists>

  <build>
    <plugins>
      <plugin>
        <groupId>inheritance.configuration</groupId>

import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Marks an event subscriber method as being thread-safe. This annotation indicates that EventBus
 * may invoke the event subscriber simultaneously from multiple threads.
 *
 * <p>This does not mark the method, and so should be used in combination with {@link Subscribe}.
 *
 * @author Cliff Biffle
 * @since 10.0
 */
@Retention(RetentionPolicy.RUNTIME)

    Iterator<Subscriber> two = registry.getSubscribers("");
    assertEquals(s1, two.next().target);
    assertEquals(o1, two.next().target);
    assertFalse(two.hasNext());
  }

  public static class StringSubscriber {

    @Subscribe
    public void handle(String s) {}
  }

  public static class IntegerSubscriber {

    @Subscribe
    public void handle(Integer i) {}
  }