/**
     * Unregisters a previously registered listener.
     *
     * @param listener the listener to unregister
     * @throws NullPointerException if {@code listener} is null
     */
    void unregisterListener(@Nonnull Listener listener);

    /**
     * Returns the list of registered listeners.
     *
     * @return an immutable collection of listeners, never {@code null}

   * difficult to reproduce because they depend on timing. For example:
   *
   * <ul>
   *   <li>When a {@code ListenableFuture} listener is registered to run under {@code
   *       directExecutor}, the listener can execute in any of three possible threads:
   *       <ol>
   *         <li>When a thread attaches a listener to a {@code ListenableFuture} that's already

 * ---------------------------------------------
 * JMORRIS2        <00>  UNIQUE      Registered
 * BILLING-NY      <00>  GROUP       Registered
 * JMORRIS2        <03>  UNIQUE      Registered
 * JMORRIS2        <20>  UNIQUE      Registered
 * BILLING-NY      <1E>  GROUP       Registered
 * JMORRIS         <03>  UNIQUE      Registered
 * 
 * MAC Address = 00-B0-34-21-FA-3B
 * </pre>
 * 
 * </blockquote>

    /** The key of the configuration. e.g. businessCategory */
    String LDAP_ATTR_BUSINESS_CATEGORY = "ldap.attr.businessCategory";

    /** The key of the configuration. e.g. registeredAddress */
    String LDAP_ATTR_REGISTERED_ADDRESS = "ldap.attr.registeredAddress";

    /** The key of the configuration. e.g. displayName */
    String LDAP_ATTR_DISPLAY_NAME = "ldap.attr.displayName";

    }
  }

  public void testDeadEventForwarding() {
    GhostCatcher catcher = new GhostCatcher();
    bus.register(catcher);

    // A String -- an event for which no one has registered.
    bus.post(EVENT);

    List<DeadEvent> events = catcher.getEvents();
    assertEquals("One dead event should be delivered.", 1, events.size());

    }
  }

  public void testDeadEventForwarding() {
    GhostCatcher catcher = new GhostCatcher();
    bus.register(catcher);

    // A String -- an event for which no one has registered.
    bus.post(EVENT);

    List<DeadEvent> events = catcher.getEvents();
    assertEquals("One dead event should be delivered.", 1, events.size());

  /**
   * Map generator that verifies that {@code setUp()} methods are called in all the test cases. The
   * {@code setUpRan} parameter is set true by the {@code setUp} that every test case is supposed to
   * have registered, and set false by the {@code tearDown}. We use a dynamic proxy to intercept all
   * of the {@code Map} method calls and check that {@code setUpRan} is true.
   */

  /**
   * Map generator that verifies that {@code setUp()} methods are called in all the test cases. The
   * {@code setUpRan} parameter is set true by the {@code setUp} that every test case is supposed to
   * have registered, and set false by the {@code tearDown}. We use a dynamic proxy to intercept all
   * of the {@code Map} method calls and check that {@code setUpRan} is true.
   */

   * signal the first active guard that is satisfied. But the corresponding thread may have already
   * been interrupted and is waiting to reacquire the lock while still registered in activeGuards,
   * in which case the signal is a no-op, and the bigger-picture signal is lost unless interrupted
   * threads take special action by participating in the signal-passing game.
   */

  /*

 * events to it.
 *
 * <p>Two subscribers are equivalent when they refer to the same method on the same object (not
 * class). This property is used to ensure that no subscriber method is registered more than once.
 *
 * @author Colin Decker
 */
@ElementTypesAreNonnullByDefault
class Subscriber {

  /** Creates a {@code Subscriber} for {@code method} on {@code listener}. */