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com.vaadin.flow.server.streams.
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.

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