Java 类javax.servlet.http.HttpSessionAttributeListener 实例源码

/**
 * This method is used by injected code to register listeners for
 * {@link ServletContext}. If object argument is a {@link ServletContext} and
 * listener argument contains {@link HttpSessionListener} or
 * {@link HttpSessionAttributeListener}, the method will add them to list of
 * known listeners associated to {@link ServletContext}
 *
 * @param servletContext
 *          the active servlet context
 * @param listener
 *          the listener to use
 */
public void onAddListener(ServletContext servletContext, Object listener) {
  String contextPath = servletContext.getContextPath();
  ServletContextDescriptor scd = getDescriptor(servletContext);
  logger.debug("Registering listener {} for context {}", listener, contextPath);
  // As theoretically one class can implement many listener interfaces we
  // check if it implements each of supported ones
  if (listener instanceof HttpSessionListener) {
    scd.addHttpSessionListener((HttpSessionListener)listener);
  }
  if (listener instanceof HttpSessionAttributeListener) {
    scd.addHttpSessionAttributeListener((HttpSessionAttributeListener)listener);
  }
  if (ServletLevel.isServlet31) {
    // Guard the code inside block to avoid use of classes
    // that are not available in versions before Servlet 3.1
    if (listener instanceof HttpSessionIdListener) { // NOSONAR
      scd.addHttpSessionIdListener((HttpSessionIdListener)listener);
    }
  }
}

/**
 * Init method called by the main servlet when the wrapping servlet is initialized. This means that the context is
 * taken into service by the system.
 *
 * @param parent The parent servlet context. Just for some delegation actions
 */
void init(ServletContext parent) {
    // Set up the tracking of event listeners.
    BundleContext bc = getOwner().getBundleContext();
    delegate = parent;
    Collection<Class<? extends EventListener>> toTrack = Arrays.asList(HttpSessionListener.class,
            ServletRequestListener.class, HttpSessionAttributeListener.class, ServletRequestAttributeListener.class,
            ServletContextListener.class);
    Collection<String> objectFilters = toTrack.stream().
            map((c) -> "(" + Constants.OBJECTCLASS + "=" + c.getName() + ")").collect(Collectors.toList());
    String filterString = "|" + String.join("", objectFilters);
    eventListenerTracker = startTracking(filterString,
            new Tracker<EventListener, EventListener>(bc, getContextPath(), (e) -> e, (e) -> { /* No destruct */}));
    // Initialize the servlets.
    ServletContextEvent event = new ServletContextEvent(this);
    call(ServletContextListener.class, (l) -> l.contextInitialized(event));
    servlets.values().forEach((s) -> init(s));
    // And the filters.
    filters.values().forEach((f) -> init(f));
    // Set up the tracking of servlets and filters.
    servletTracker = startTracking(Constants.OBJECTCLASS + "=" + Servlet.class.getName(),
            new Tracker<Servlet, String>(bc, getContextPath(), this::addServlet, this::removeServlet));
    filterTracker = startTracking(Constants.OBJECTCLASS + "=" + Filter.class.getName(),
            new Tracker<Filter, String>(bc, getContextPath(), this::addFilter, this::removeFilter));
}

@Override
public void setAttribute(String name, Object value) {
    // According to the specifications, a value of null should be handled as a remove.
    if (value == null) {
        removeAttribute(name);
        return;
    }
    checkValid();
    // See how to notify our listeners: as a replacement or an addition.
    BiConsumer<HttpSessionAttributeListener, HttpSessionBindingEvent> notifier = (l, e) -> l.attributeAdded(e);
    if (unbindOriginal(name)) {
        notifier = (l, e) -> l.attributeReplaced(e);
    }
    // Update the data.
    attributes.put(name, value);
    // And perform the notification.
    notifyListeners(name, value, notifier);
}

private void notifyListeners(String name, Object oldValue, Object value) {
    if (listeners != null) {
    HttpSessionBindingEvent event = new HttpSessionBindingEvent(this, name, value);
    HttpSessionBindingEvent oldEvent = oldValue == null ? null : new HttpSessionBindingEvent(this, name,
        oldValue);
    for (int i = 0, n = listeners.size(); i < n; i++)
        try {
        HttpSessionAttributeListener l = (HttpSessionAttributeListener) listeners.get(i);
        if (oldEvent != null)
            l.attributeReplaced(oldEvent);
        l.attributeAdded(event);
        } catch (ClassCastException cce) {
        } catch (NullPointerException npe) {
        }
    }
}

private static boolean isWeb(final Class<?> beanClass) {
    if (Servlet.class.isAssignableFrom(beanClass)
        || Filter.class.isAssignableFrom(beanClass)) {
        return true;
    }
    if (EventListener.class.isAssignableFrom(beanClass)) {
        return HttpSessionAttributeListener.class.isAssignableFrom(beanClass)
               || ServletContextListener.class.isAssignableFrom(beanClass)
               || ServletRequestListener.class.isAssignableFrom(beanClass)
               || ServletContextAttributeListener.class.isAssignableFrom(beanClass)
               || HttpSessionListener.class.isAssignableFrom(beanClass)
               || HttpSessionBindingListener.class.isAssignableFrom(beanClass)
               || HttpSessionActivationListener.class.isAssignableFrom(beanClass)
               || HttpSessionIdListener.class.isAssignableFrom(beanClass)
               || ServletRequestAttributeListener.class.isAssignableFrom(beanClass);
    }

    return false;
}

@Override
public <T extends EventListener> void addListener(T t) {
    if (!context.getState().equals(LifecycleState.STARTING_PREP)) {
        throw new IllegalStateException(
                sm.getString("applicationContext.addListener.ise",
                        getContextPath()));
    }

    boolean match = false;
    if (t instanceof ServletContextAttributeListener ||
            t instanceof ServletRequestListener ||
            t instanceof ServletRequestAttributeListener ||
            t instanceof HttpSessionAttributeListener) {
        context.addApplicationEventListener(t);
        match = true;
    }

    if (t instanceof HttpSessionListener
            || (t instanceof ServletContextListener &&
                    newServletContextListenerAllowed)) {
        // Add listener directly to the list of instances rather than to
        // the list of class names.
        context.addApplicationLifecycleListener(t);
        match = true;
    }

    if (match) return;

    if (t instanceof ServletContextListener) {
        throw new IllegalArgumentException(sm.getString(
                "applicationContext.addListener.iae.sclNotAllowed",
                t.getClass().getName()));
    } else {
        throw new IllegalArgumentException(sm.getString(
                "applicationContext.addListener.iae.wrongType",
                t.getClass().getName()));
    }
}

@Override
public <T extends EventListener> void addListener(T t) {
    if (!context.getState().equals(LifecycleState.STARTING_PREP)) {
        throw new IllegalStateException(
                sm.getString("applicationContext.addListener.ise",
                        getContextPath()));
    }

    boolean match = false;
    if (t instanceof ServletContextAttributeListener ||
            t instanceof ServletRequestListener ||
            t instanceof ServletRequestAttributeListener ||
            t instanceof HttpSessionAttributeListener) {
        context.addApplicationEventListener(t);
        match = true;
    }

    if (t instanceof HttpSessionListener
            || (t instanceof ServletContextListener &&
                    newServletContextListenerAllowed)) {
        // Add listener directly to the list of instances rather than to
        // the list of class names.
        context.addApplicationLifecycleListener(t);
        match = true;
    }

    if (match) return;

    if (t instanceof ServletContextListener) {
        throw new IllegalArgumentException(sm.getString(
                "applicationContext.addListener.iae.sclNotAllowed",
                t.getClass().getName()));
    } else {
        throw new IllegalArgumentException(sm.getString(
                "applicationContext.addListener.iae.wrongType",
                t.getClass().getName()));
    }
}

@Override
public <T extends EventListener> void addListener(T t) {
    if (!context.getState().equals(LifecycleState.STARTING_PREP)) {
        throw new IllegalStateException(sm.getString("applicationContext.addListener.ise", getContextPath()));
    }

    boolean match = false;
    if (t instanceof ServletContextAttributeListener || t instanceof ServletRequestListener
            || t instanceof ServletRequestAttributeListener || t instanceof HttpSessionAttributeListener) {
        context.addApplicationEventListener(t);
        match = true;
    }

    if (t instanceof HttpSessionListener
            || (t instanceof ServletContextListener && newServletContextListenerAllowed)) {
        // Add listener directly to the list of instances rather than to
        // the list of class names.
        context.addApplicationLifecycleListener(t);
        match = true;
    }

    if (match)
        return;

    if (t instanceof ServletContextListener) {
        throw new IllegalArgumentException(
                sm.getString("applicationContext.addListener.iae.sclNotAllowed", t.getClass().getName()));
    } else {
        throw new IllegalArgumentException(
                sm.getString("applicationContext.addListener.iae.wrongType", t.getClass().getName()));
    }
}

/**
 * Notifies listeners that attribute was added. See {@link SessionNotifier}
 * {@link #attributeAdded(RepositoryBackedSession, String, Object)}.
 * <p>
 * If the added attribute <code>value</code> is a HttpSessionBindingListener,
 * it will receive the {@link HttpSessionBindingEvent}. If there are
 * {@link HttpSessionAttributeListener} instances associated to
 * {@link ServletContext}, they will be notified via
 * {@link HttpSessionAttributeListener#attributeAdded(HttpSessionBindingEvent)}
 * .
 */
@Override
public void attributeAdded(RepositoryBackedSession session, String key, Object value) {
  // If the
  if (session instanceof HttpSession && value instanceof HttpSessionBindingListener) {
    ((HttpSessionBindingListener)value).valueBound(new HttpSessionBindingEvent((HttpSession)session, key));
  }
  HttpSessionBindingEvent event = new HttpSessionBindingEvent((HttpSession)session, key, value);
  for (HttpSessionAttributeListener listener : descriptor.getHttpSessionAttributeListeners()) {
    listener.attributeAdded(event);
  }
}

@Test
public void testOnAddListener() {
  ServletContextDescriptor scd = new ServletContextDescriptor(servletContext);
  when(servletContext.getAttribute(Attributes.SERVLET_CONTEXT_DESCRIPTOR)).thenReturn(scd);
  sessionHelpers.onAddListener(servletContext, "Dummy");
  assertTrue(scd.getHttpSessionListeners().isEmpty());
  assertTrue(scd.getHttpSessionIdListeners().isEmpty());
  assertTrue(scd.getHttpSessionAttributeListeners().isEmpty());
  HttpSessionListener listener = mock(HttpSessionListener.class);
  HttpSessionIdListener idListener = mock(HttpSessionIdListener.class);
  HttpSessionAttributeListener attributeListener = mock(HttpSessionAttributeListener.class);
  HttpSessionListener multiListener = mock(HttpSessionListener.class,
      withSettings().extraInterfaces(HttpSessionAttributeListener.class));
  HttpSessionAttributeListener attributeMultiListener = (HttpSessionAttributeListener)multiListener;
  sessionHelpers.onAddListener(servletContext, listener);
  assertThat(scd.getHttpSessionListeners(), hasItem(listener));
  assertTrue(scd.getHttpSessionIdListeners().isEmpty());
  assertTrue(scd.getHttpSessionAttributeListeners().isEmpty());
  sessionHelpers.onAddListener(servletContext, idListener);
  assertThat(scd.getHttpSessionListeners(), hasItem(listener));
  assertThat(scd.getHttpSessionIdListeners(), hasItem(idListener));
  assertTrue(scd.getHttpSessionAttributeListeners().isEmpty());
  sessionHelpers.onAddListener(servletContext, attributeListener);
  assertThat(scd.getHttpSessionListeners(), hasItem(listener));
  assertThat(scd.getHttpSessionIdListeners(), hasItem(idListener));
  assertThat(scd.getHttpSessionAttributeListeners(), hasItem(attributeListener));
  sessionHelpers.onAddListener(servletContext, multiListener);
  assertThat(scd.getHttpSessionListeners(), hasItem(listener));
  assertThat(scd.getHttpSessionListeners(), hasItem(multiListener));
  assertThat(scd.getHttpSessionIdListeners(), hasItem(idListener));
  assertThat(scd.getHttpSessionAttributeListeners(), hasItem(attributeListener));
  assertThat(scd.getHttpSessionAttributeListeners(), hasItem(attributeMultiListener));
}

@Test
public void testAttributeAdded() {
  HttpSessionAttributeListener listener = mock(HttpSessionAttributeListener.class);
  descriptor.addHttpSessionAttributeListener(listener);
  notifier.attributeAdded(session, "Test", "value");
  verify(listener).attributeAdded(any(HttpSessionBindingEvent.class));
  HttpSessionBindingListener bindingListener = mock(HttpSessionBindingListener.class);
  notifier.attributeAdded(session, "Test", bindingListener);
  verify(listener, times(2)).attributeAdded(any(HttpSessionBindingEvent.class));
  verify(bindingListener).valueBound(any(HttpSessionBindingEvent.class));
}

@Test
public void testAttributeReplaced() {
  HttpSessionAttributeListener listener = mock(HttpSessionAttributeListener.class);
  notifier.attributeReplaced(session, "Test", "very-old-value");
  verify(listener, never()).attributeReplaced(any(HttpSessionBindingEvent.class));
  descriptor.addHttpSessionAttributeListener(listener);
  notifier.attributeReplaced(session, "Test", "old-value");
  verify(listener).attributeReplaced(any(HttpSessionBindingEvent.class));
  HttpSessionBindingListener bindingListener = mock(HttpSessionBindingListener.class);
  notifier.attributeReplaced(session, "Test", bindingListener);
  verify(listener, times(2)).attributeReplaced(any(HttpSessionBindingEvent.class));
  verify(bindingListener).valueUnbound(any(HttpSessionBindingEvent.class));
}

@Test
public void testAttributeRemoved() {
  notifier.attributeRemoved(session, "Test", "very-old-value");
  HttpSessionAttributeListener listener = mock(HttpSessionAttributeListener.class);
  descriptor.addHttpSessionAttributeListener(listener);
  notifier.attributeRemoved(session, "Test", "old-value");
  verify(listener).attributeRemoved(any(HttpSessionBindingEvent.class));
  HttpSessionBindingListener bindingListener = mock(HttpSessionBindingListener.class);
  notifier.attributeRemoved(session, "Test", bindingListener);
  verify(listener, times(2)).attributeRemoved(any(HttpSessionBindingEvent.class));
  verify(bindingListener).valueUnbound(any(HttpSessionBindingEvent.class));
}

public void sessionDidActivate(HttpSessionEvent se) {
    for (EventListener listener: PluginWebInstanceRepository.getListeners()) {
        if (listener instanceof HttpSessionAttributeListener) {
            ((HttpSessionActivationListener) listener).sessionDidActivate(se);
        }
    }
}

public void attributeAdded(HttpSessionBindingEvent se) {
    for (EventListener listener: PluginWebInstanceRepository.getListeners()) {
        if (listener instanceof HttpSessionAttributeListener) {
            ((HttpSessionAttributeListener) listener).attributeAdded(se);
        }
    }
}

public void attributeRemoved(HttpSessionBindingEvent se) {
    for (EventListener listener: PluginWebInstanceRepository.getListeners()) {
        if (listener instanceof HttpSessionAttributeListener) {
            ((HttpSessionAttributeListener) listener).attributeRemoved(se);
        }
    }
}

public void attributeReplaced(HttpSessionBindingEvent se) {
    for (EventListener listener: PluginWebInstanceRepository.getListeners()) {
        if (listener instanceof HttpSessionAttributeListener) {
            ((HttpSessionAttributeListener) listener).attributeReplaced(se);
        }
    }
}

private void loadListeners(WebAppConfiguration wac)
    throws ClassNotFoundException, IllegalAccessException,
    InstantiationException, WebAppConfigurationException {
  for (WebAppListener listener : wac.getListeners()) {
    String className = listener.getListenerClass();
    Class<?> clazz = classLoader.loadClass(className);
    Object obj = clazz.newInstance();
    boolean used = false;
    if (obj instanceof ServletContextAttributeListener) {
      scaListeners.add((ServletContextAttributeListener) obj);
      used = true;
    }
    if (obj instanceof ServletContextListener) {
      scListeners.add((ServletContextListener) obj);
      used = true;
    }
    if (obj instanceof ServletRequestListener) {
      srListeners.add((ServletRequestListener) obj);
      used = true;
    }
    if (obj instanceof ServletRequestAttributeListener) {
      sraListeners.add((ServletRequestAttributeListener) obj);
      used = true;
    }
    if (obj instanceof HttpSessionAttributeListener) {
      sessionAttributeListeners.add((HttpSessionAttributeListener) obj);
      used = true;
    }
    if (obj instanceof HttpSessionListener) {
      sessionListeners.add((HttpSessionListener) obj);
      used = true;
    }
    if (!used) {
      throw new WebAppConfigurationException("Don't know what to do with '"
          + className + "'");
    }
  }
}

public WebAppSessionWrapper(HttpSession delegate, ServletContext context,
    HttpSessionListener sessionListener,
    HttpSessionAttributeListener sessionAttributeListener) {
  super(delegate);
  this.context = context;
  this.sessionListener = sessionListener;
  this.sessionAttributeListener = sessionAttributeListener;
  fireSessionCreated();
}

private void addListenerInstance(final Object listenerInstance,
        final List<ServletContextAttributeListener> contextAttributeListeners,
        final List<ServletContextListener> contextListeners,
        final List<ServletRequestAttributeListener> requestAttributeListeners,
        final List<ServletRequestListener> requestListeners, final List<HttpSessionActivationListener> sessionActivationListeners,
        final List<HttpSessionAttributeListener> sessionAttributeListeners, final List<HttpSessionListener> sessionListeners) {
    if (listenerInstance instanceof ServletContextAttributeListener) {
        contextAttributeListeners.add((ServletContextAttributeListener) listenerInstance);
    }
    if (listenerInstance instanceof ServletContextListener) {
        contextListeners.add((ServletContextListener) listenerInstance);
    }
    if (listenerInstance instanceof ServletRequestAttributeListener) {
        requestAttributeListeners.add((ServletRequestAttributeListener) listenerInstance);
    }
    if (listenerInstance instanceof ServletRequestListener) {
        requestListeners.add((ServletRequestListener) listenerInstance);
    }
    if (listenerInstance instanceof HttpSessionActivationListener) {
        sessionActivationListeners.add((HttpSessionActivationListener) listenerInstance);
    }
    if (listenerInstance instanceof HttpSessionAttributeListener) {
        sessionAttributeListeners.add((HttpSessionAttributeListener) listenerInstance);
    }
    if (listenerInstance instanceof HttpSessionListener) {
        sessionListeners.add((HttpSessionListener) listenerInstance);
    }
}

@Override
public void removeAttribute(String name) {
    access();
    sessionManager.getSessionStorage().removeSessionAttribute(getId(), name);
    Object value = attributes.remove(name);

    if(null == value){
        return;
    }

    HttpSessionBindingEvent event = null;
    if(null != value && value instanceof HttpSessionBindingListener){
        event = new HttpSessionBindingEvent(this, name, value);
        try{
            ((HttpSessionBindingListener)value).valueUnbound(event);
        }catch (Exception e){
            logger.error("bingEvent error:", e);
            throw new RuntimeException(e);
        }
    }

    List<EventListener> listeners = sessionManager.getEventListeners();
    for(EventListener eventListener : listeners){
        if(!(eventListener instanceof HttpSessionAttributeListener)){
            continue;
        }

        HttpSessionAttributeListener listener = (HttpSessionAttributeListener) eventListener;
        if(event == null){
            event = new HttpSessionBindingEvent(this, name, value);
        }
        listener.attributeRemoved(event);
    }
}

@Override
public void removeAttribute(String name) {
    access();
    Object value = getAttribute(name);

    if(null == value){
        return;
    }

    HttpSessionBindingEvent event = null;
    sessionManager.getSessionStorage().removeSessionAttribute(getId(), name);
    if(null != value && value instanceof HttpSessionBindingListener){
        event = new HttpSessionBindingEvent(this, name);
        try{
            ((HttpSessionBindingListener)value).valueUnbound(event);
        }catch (Exception e){
            logger.error("bingEvent error:", e);
            throw new RuntimeException(e);
        }
    }


    List<EventListener> listeners = sessionManager.getEventListeners();
    for(EventListener eventListener : listeners){
        if(!(eventListener instanceof HttpSessionAttributeListener)){
            continue;
        }

        HttpSessionAttributeListener listener = (HttpSessionAttributeListener) eventListener;
        if(event == null){
            event = new HttpSessionBindingEvent(this, name, value);
        }
        listener.attributeRemoved(event);
    }
}

@Override
public <T extends EventListener> void addListener(T t) {
    if (!context.getState().equals(LifecycleState.STARTING_PREP)) {
        throw new IllegalStateException(
                sm.getString("applicationContext.addListener.ise",
                        getContextPath()));
    }

    boolean match = false;
    if (t instanceof ServletContextAttributeListener ||
            t instanceof ServletRequestListener ||
            t instanceof ServletRequestAttributeListener ||
            t instanceof HttpSessionAttributeListener) {
        context.addApplicationEventListener(t);
        match = true;
    }

    if (t instanceof HttpSessionListener
            || (t instanceof ServletContextListener &&
                    newServletContextListenerAllowed)) {
        // Add listener directly to the list of instances rather than to
        // the list of class names.
        context.addApplicationLifecycleListener(t);
        match = true;
    }

    if (match) return;

    if (t instanceof ServletContextListener) {
        throw new IllegalArgumentException(sm.getString(
                "applicationContext.addListener.iae.sclNotAllowed",
                t.getClass().getName()));
    } else {
        throw new IllegalArgumentException(sm.getString(
                "applicationContext.addListener.iae.wrongType",
                t.getClass().getName()));
    }
}

@Override
public <T extends EventListener> void addListener(T t) {
    if (!context.getState().equals(LifecycleState.STARTING_PREP)) {
        throw new IllegalStateException(
                sm.getString("applicationContext.addListener.ise",
                        getContextPath()));
    }

    boolean match = false;
    if (t instanceof ServletContextAttributeListener ||
            t instanceof ServletRequestListener ||
            t instanceof ServletRequestAttributeListener ||
            t instanceof HttpSessionAttributeListener) {
        context.addApplicationEventListener(t);
        match = true;
    }

    if (t instanceof HttpSessionListener
            || (t instanceof ServletContextListener &&
                    newServletContextListenerAllowed)) {
        // Add listener directly to the list of instances rather than to
        // the list of class names.
        context.addApplicationLifecycleListener(t);
        match = true;
    }

    if (match) return;

    if (t instanceof ServletContextListener) {
        throw new IllegalArgumentException(sm.getString(
                "applicationContext.addListener.iae.sclNotAllowed",
                t.getClass().getName()));
    } else {
        throw new IllegalArgumentException(sm.getString(
                "applicationContext.addListener.iae.wrongType",
                t.getClass().getName()));
    }
}

@Override
public <T extends EventListener> void addListener(T t) {
    if (!context.getState().equals(LifecycleState.STARTING_PREP)) {
        throw new IllegalStateException(
                sm.getString("applicationContext.addListener.ise",
                        getContextPath()));
    }

    boolean match = false;
    if (t instanceof ServletContextAttributeListener ||
            t instanceof ServletRequestListener ||
            t instanceof ServletRequestAttributeListener ||
            t instanceof HttpSessionAttributeListener) {
        context.addApplicationEventListener(t);
        match = true;
    }

    if (t instanceof HttpSessionListener
            || (t instanceof ServletContextListener &&
                    newServletContextListenerAllowed)) {
        // Add listener directly to the list of instances rather than to
        // the list of class names.
        context.addApplicationLifecycleListener(t);
        match = true;
    }

    if (match) return;

    if (t instanceof ServletContextListener) {
        throw new IllegalArgumentException(sm.getString(
                "applicationContext.addListener.iae.sclNotAllowed",
                t.getClass().getName()));
    } else {
        throw new IllegalArgumentException(sm.getString(
                "applicationContext.addListener.iae.wrongType",
                t.getClass().getName()));
    }
}

@Override
public void attributeAdded(final HttpSessionBindingEvent se)
{
    final Iterator<HttpSessionAttributeListener> listeners = getContextListeners();
    while (listeners.hasNext())
    {
        listeners.next().attributeAdded(se);
    }
}

@Override
public void attributeRemoved(final HttpSessionBindingEvent se)
{
    final Iterator<HttpSessionAttributeListener> listeners = getContextListeners();
    while (listeners.hasNext())
    {
        listeners.next().attributeRemoved(se);
    }
}

@Override
public void attributeReplaced(final HttpSessionBindingEvent se)
{
    final Iterator<HttpSessionAttributeListener> listeners = getContextListeners();
    while (listeners.hasNext())
    {
        listeners.next().attributeReplaced(se);
    }
}

private void notifyListeners(String name, Object value) {
    if (listeners != null) {
    HttpSessionBindingEvent event = new HttpSessionBindingEvent(this, name, value);
    for (int i = 0, n = listeners.size(); i < n; i++)
        try {
        ((HttpSessionAttributeListener) listeners.get(i)).attributeRemoved(event);
        } catch (ClassCastException cce) {
        } catch (NullPointerException npe) {
        }
    }
}

public void httpSessionAttributeAdded(final HttpSession session, final String name, final Object value) {
    final HttpSessionBindingEvent sre = new HttpSessionBindingEvent(session, name, value);
    for (int i = 0; i < httpSessionAttributeListeners.length; ++i) {
        this.<HttpSessionAttributeListener>get(httpSessionAttributeListeners[i]).attributeAdded(sre);
    }
}

public void httpSessionAttributeRemoved(final HttpSession session, final String name, final Object value) {
    final HttpSessionBindingEvent sre = new HttpSessionBindingEvent(session, name, value);
    for (int i = 0; i < httpSessionAttributeListeners.length; ++i) {
        this.<HttpSessionAttributeListener>get(httpSessionAttributeListeners[i]).attributeRemoved(sre);
    }
}

public void httpSessionAttributeReplaced(final HttpSession session, final String name, final Object value) {
    final HttpSessionBindingEvent sre = new HttpSessionBindingEvent(session, name, value);
    for (int i = 0; i < httpSessionAttributeListeners.length; ++i) {
        this.<HttpSessionAttributeListener>get(httpSessionAttributeListeners[i]).attributeReplaced(sre);
    }
}

/**
 * Remove the object bound with the specified name from this session.  If
 * the session does not have an object bound with this name, this method
 * does nothing.
 * <p>
 * After this method executes, and if the object implements
 * <code>HttpSessionBindingListener</code>, the container calls
 * <code>valueUnbound()</code> on the object.
 *
 * @param name Name of the object to remove from this session.
 * @param notify Should we notify interested listeners that this
 *  attribute is being removed?
 *
 * @exception IllegalStateException if this method is called on an
 *  invalidated session
 */
public void removeAttribute(String name, boolean notify) {

    // Validate our current state
    if (!expiring && !isValid)
        throw new IllegalStateException
            (sm.getString("standardSession.removeAttribute.ise"));

    // Remove this attribute from our collection
    Object value = null;
    boolean found = false;
    synchronized (attributes) {
        found = attributes.containsKey(name);
        if (found) {
            value = attributes.get(name);
            attributes.remove(name);
        } else {
            return;
        }
    }

    // Do we need to do valueUnbound() and attributeRemoved() notification?
    if (!notify) {
        return;
    }

    // Call the valueUnbound() method if necessary
    HttpSessionBindingEvent event =
      new HttpSessionBindingEvent((HttpSession) this, name, value);
    if ((value != null) &&
        (value instanceof HttpSessionBindingListener))
        ((HttpSessionBindingListener) value).valueUnbound(event);

    // Notify interested application event listeners
    Context context = (Context) manager.getContainer();
    Object listeners[] = context.getApplicationListeners();
    if (listeners == null)
        return;
    for (int i = 0; i < listeners.length; i++) {
        if (!(listeners[i] instanceof HttpSessionAttributeListener))
            continue;
        HttpSessionAttributeListener listener =
            (HttpSessionAttributeListener) listeners[i];
        try {
            fireContainerEvent(context,
                               "beforeSessionAttributeRemoved",
                               listener);
            listener.attributeRemoved(event);
            fireContainerEvent(context,
                               "afterSessionAttributeRemoved",
                               listener);
        } catch (Throwable t) {
            try {
                fireContainerEvent(context,
                                   "afterSessionAttributeRemoved",
                                   listener);
            } catch (Exception e) {
                ;
            }
            // FIXME - should we do anything besides log these?
            log(sm.getString("standardSession.attributeEvent"), t);
        }
    }

}

@Override
public void attributeAdded(HttpSessionBindingEvent event) {
    ((HttpSessionAttributeListener)delegate).attributeAdded(event);
}

@Override
public void attributeRemoved(HttpSessionBindingEvent event) {
    ((HttpSessionAttributeListener)delegate).attributeRemoved(event);
}

@Override
public void attributeReplaced(HttpSessionBindingEvent event) {
    ((HttpSessionAttributeListener)delegate).attributeReplaced(event);
}

HttpSessionAttributeListener getHttpSessionAttributeListener() {
    return this.sessionAttributeListener;
}

private void initHttpSessionAttributeListener(EventListener listener) {
    if (listener instanceof HttpSessionAttributeListener) {
        this.sessionAttributeListener = (HttpSessionAttributeListener) listener;
    }
}

public HttpSessionAttributeListener getHttpSessionAttributeListener() {
  return sessionAttributeListeners;
}

public HttpSessionAttributeListener getHttpSessionAttributeListener() {
  return null;
}