Package com.vaadin.flow.server.streams

Interface ElementRequestHandler

All Superinterfaces:

Serializable

All Known Subinterfaces:

DownloadHandler, UploadHandler

All Known Implementing Classes:

AbstractDownloadHandler, AbstractFileUploadHandler, ClassDownloadHandler, FileDownloadHandler, FileUploadHandler, InMemoryUploadHandler, InputStreamDownloadHandler, ServletResourceDownloadHandler, TemporaryFileUploadHandler

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 ElementRequestHandler
extends Serializable

Request handler callback for handing client-server or server-client data transfer scoped to a specific (owner) element.

Method Summary

Modifier and Type	Method	Description
default DisabledUpdateMode	getDisabledUpdateMode()	Controls whether request handler is invoked when the owner element is disabled.
default String	getUrlPostfix()	Optional URL postfix allows appending an application-controlled string, e.g.
void	handleRequest(VaadinRequest request, VaadinResponse response, VaadinSession session, Element owner)	Request handler callback for handing client-server or server-client data transfer scoped to a specific (owner) element.
default boolean	isAllowInert()	Whether to invoke this request handler even if the owning element is currently inert.

Method Details

handleRequest

void handleRequest(VaadinRequest request,
 VaadinResponse response,
 VaadinSession session,
 Element owner)
            throws IOException

Request handler callback for handing client-server or server-client data transfer scoped to a specific (owner) element. Note: when handling requests via this API, you need to take care of typical stream handling issues, e.g. exceptions yourself. However, you do not need to close the stream yourself, Flow will handle that for you when needed.

Parameters:

request - VaadinRequest request to handle

response - VaadinResponse response to handle

session - VaadinSession current VaadinSession

owner - Element owner element

Throws:

IOException - if an IO error occurred during data transfer

getUrlPostfix

default String getUrlPostfix()

Optional URL postfix allows appending an application-controlled string, e.g. the logical name of the target file, to the end of the otherwise random-looking download URL. If defined, requests that would otherwise be routable are still rejected if the postfix is missing or invalid. Postfix changes the last segment in the resource url.

Returns:

String optional URL postfix, or null for "".

isAllowInert

default boolean isAllowInert()

Whether to invoke this request handler even if the owning element is currently inert.

Returns:

true to invoke for inert elements, false otherwise. Defaults to false.

getDisabledUpdateMode

default DisabledUpdateMode getDisabledUpdateMode()

Controls whether request handler is invoked when the owner element is disabled.

Returns:

the currently set DisabledUpdateMode for this request handler. Defaults to ONLY_WHEN_ENABLED.