Class VaadinUtils

java.lang.Object

com.vaadin.swingbridge.surrogates.util.VaadinUtils

public final class VaadinUtils
extends Object

Broad, generic Vaadin UI/DOM utilities used across the surrogate layer; shared with :emulators in the SD_shelper_statics-allowed direction where needed.

Method Summary

Modifier and Type	Method	Description
static void	injectStyleOnce(com.vaadin.flow.component.UI ui, String sentinelKey, String dataEmulValue, String css)	Inject a server-managed <style> element into the given UI's element tree exactly once, guarded by a per-UI sentinel.

Methods inherited from class Object

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

Method Details

injectStyleOnce

public static void injectStyleOnce(com.vaadin.flow.component.UI ui,
 String sentinelKey,
 String dataEmulValue,
 String css)

Inject a server-managed <style> element into the given UI's element tree exactly once, guarded by a per-UI sentinel. Generic mechanism behind pseudo-element CSS that inline Style can't reach (e.g. BorderCss's TitledBorder ::before rule, SJProgressBar's progress-string ::after rule).

The <style> lives in the UI element tree rather than going through Page.executeJs(String, Object...) / addStyleSheet: only a tree-attached Element survives a @PreserveOnRefresh reload, because Vaadin re-renders the preserved tree (it doesn't replay executeJs or re-emit already-sent dependencies). The sentinelKey guards against double-attach on a single UI and survives reload for the same reason.

Parameters:

ui - the target UI; no-op when null

sentinelKey - per-UI ComponentUtil data key marking "already injected"

dataEmulValue - value for the data-emul attribute on the <style> (identifies the rule in DevTools)

css - the stylesheet text