com.vaadin.server

Interface RequestHandler

All Superinterfaces:

Serializable

All Known Subinterfaces:

SessionExpiredHandler

All Known Implementing Classes:

BootstrapHandler, ConnectorResourceHandler, FileUploadHandler, GlobalResourceHandler, HeartbeatHandler, PortletBootstrapHandler, PortletDummyRequestHandler, PortletListenerNotifier, PortletStateAwareRequestHandler, PortletUIInitHandler, PublishedFileHandler, PushRequestHandler, ServletBootstrapHandler, ServletUIInitHandler, SessionRequestHandler, SynchronizedRequestHandler, UidlRequestHandler, UIInitHandler, UnsupportedBrowserHandler

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface RequestHandler
extends Serializable

Handler for producing a response to HTTP requests. Handlers can be either added on a service level, common for all users, or on a session level for only a single user.

Method Summary

Modifier and Type	Method and Description
boolean	handleRequest(VaadinSession session, VaadinRequest request, VaadinResponse response) Called when a request needs to be handled.

Method Detail

handleRequest

boolean handleRequest(VaadinSession session,
                      VaadinRequest request,
                      VaadinResponse response)
               throws IOException

Called when a request needs to be handled. If a response is written, this method should return true to indicate that no more request handlers should be invoked for the request.

Note that request handlers by default do not lock the session. If you are using VaadinSession or anything inside the VaadinSession you must ensure the session is locked. This can be done by extending SynchronizedRequestHandler or by using VaadinSession.accessSynchronously(Runnable) or UI.accessSynchronously(Runnable).

Parameters:

session - The session for the request

request - The request to handle

response - The response object to which a response can be written.

Returns:

true if a response has been written and no further request handlers should be called, otherwise false

Throws:

IOException - If an IO error occurred