Package com.vaadin.flow.server.streams

Class ClassDownloadHandler

java.lang.Object

com.vaadin.flow.server.streams.TransferProgressAwareHandler<DownloadEvent,R>

com.vaadin.flow.server.streams.AbstractDownloadHandler<ClassDownloadHandler>

com.vaadin.flow.server.streams.ClassDownloadHandler

All Implemented Interfaces:

DownloadHandler, ElementRequestHandler, Serializable

public class ClassDownloadHandler
extends AbstractDownloadHandler<ClassDownloadHandler>

Download handler for serving a class resource.

For instance for the file resources/com/example/ui/MyData.json and class com.example.ui.MyData the definition would be forClassResource(MyData.class, "MyData.json")

Since:

24.8

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
ClassDownloadHandler(Class<?> clazz, String resourceName)	Create a class resource download handler with the resource name as the url postfix (file name).
ClassDownloadHandler(Class<?> clazz, String resourceName, String fileName)	Create a class resource download handler with the given file name as the url postfix.

Method Summary

Modifier and Type	Method	Description
String	getUrlPostfix()	Optional URL postfix allows appending an application-controlled string, e.g.
void	handleDownloadRequest(DownloadEvent downloadEvent)	Method that is called when the client wants to download from the url stored for this specific handler registration.

Methods inherited from class com.vaadin.flow.server.streams.AbstractDownloadHandler

getContentType, getTransferContext, inline, isInline

Methods inherited from class com.vaadin.flow.server.streams.TransferProgressAwareHandler

addTransferProgressListener, getListeners, notifyError, onProgress, onProgress, onProgress, onProgress, whenComplete, whenComplete, whenStart, whenStart

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.vaadin.flow.server.streams.DownloadHandler

handleRequest

Methods inherited from interface com.vaadin.flow.server.streams.ElementRequestHandler

getDisabledUpdateMode, isAllowInert

Constructor Details

ClassDownloadHandler

public ClassDownloadHandler(Class<?> clazz,
 String resourceName)

Create a class resource download handler with the resource name as the url postfix (file name).

The downloaded file name and download URL postfix will be set to resourceName. If you want to use a different file name, use ClassDownloadHandler(Class, String, String) instead.

Parameters:

clazz - class to use for getting resource

resourceName - resource to get

ClassDownloadHandler

public ClassDownloadHandler(Class<?> clazz,
 String resourceName,
 String fileName)

Create a class resource download handler with the given file name as the url postfix.

The downloaded file name and download URL postfix will be set to fileName.

Parameters:

clazz - class to use for getting resource

resourceName - resource to get

fileName - download file name that overrides resourceName and also used as a download request URL postfix

Method Details

handleDownloadRequest

public void handleDownloadRequest(DownloadEvent downloadEvent)
                           throws IOException

Description copied from interface: DownloadHandler

Method that is called when the client wants to download from the url stored for this specific handler registration.

Parameters:

downloadEvent - download event containing the necessary data for writing the response

Throws:

IOException - if an IO error occurred during download

getUrlPostfix

public String getUrlPostfix()

Description copied from interface: ElementRequestHandler

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 "".