 An implementation of {@link VaadinSession} for JSR-286 portlet environments.
 * 
 * This is automatically registered as a {@link HttpSessionBindingListener} when
 * {@link PortletSession#setAttribute()} is called with the context as value.
 * 
 * Only the documented parts of this class should be considered as stable public
 * API.
 * 
 * Note also that some methods and/or nested interfaces might move to
 * {@link VaadinPortletService} in future minor or major versions of Vaadin. In
 * these cases, a deprecated redirection for backwards compatibility will be
 * used in VaadinPortletSession for a transition period.
 An implementation of {@link VaadinSession} for JSR-286 portlet environments.
 * 
 * This is automatically registered as a {@link HttpSessionBindingListener} when
 * {@link PortletSession#setAttribute()} is called with the context as value.
 * 
 * Only the documented parts of this class should be considered as stable public
 * API.
 * 
 * Note also that some methods and/or nested interfaces might move to
 * {@link VaadinPortletService} in future minor or major versions of Vaadin. In
 * these cases, a deprecated redirection for backwards compatibility will be
 * used in VaadinPortletSession for a transition period. | VaadinPortletSession.java