Class BorderCss

java.lang.Object

com.vaadin.swingbridge.surrogates.util.BorderCss

public final class BorderCss
extends Object

Border ↔ CSS conversion for the surrogate JComponentMixin.setBorder / getBorder path: applyBorderCss(Element, Border) writes a JDK Border as inline CSS, borderFromCss(Element) reconstructs the closest Border back (lossy per SD_border_css_lossy). Includes the TitledBorder pseudo-element rendering, whose one-off ::before rule is injected per UI via the generic VaadinUtils.injectStyleOnce(UI, String, String, String) primitive.

Color conversion delegates to CssConvert. Shared with :emulators in the SD_shelper_statics-allowed direction — the emulator vaadinx.swing.border.TitledBorder calls ensureTitledBorderStyleInjected(UI) directly.

Method Summary

Modifier and Type	Method	Description
static void	applyBorderCss(com.vaadin.flow.dom.Element element, Border border)	Write the CSS representation of border onto element.
static Border	borderFromCss(com.vaadin.flow.dom.Element element)	Reconstruct the closest JDK Border from the CSS currently written on element.
static void	clearBorderCss(com.vaadin.flow.dom.Element element)	Remove every border-related CSS key we might have written, plus the data-emul-border-title attribute that applyBorderCss(Element, Border) writes for TitledBorder.
static void	ensureTitledBorderStyleInjected(com.vaadin.flow.component.UI ui)	Ensure the [data-emul-border-title]::before rule is installed on the current page (and stays installed across @PreserveOnRefresh reloads).

Methods inherited from class Object

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

Method Details

clearBorderCss

public static void clearBorderCss(com.vaadin.flow.dom.Element element)

Remove every border-related CSS key we might have written, plus the data-emul-border-title attribute that applyBorderCss(Element, Border) writes for TitledBorder. Used before each write, and on setBorder(null).

ensureTitledBorderStyleInjected

public static void ensureTitledBorderStyleInjected(com.vaadin.flow.component.UI ui)

Ensure the [data-emul-border-title]::before rule is installed on the current page (and stays installed across @PreserveOnRefresh reloads). Thin wrapper over VaadinUtils.injectStyleOnce(UI, String, String, String); no-op when no UI is current.

applyBorderCss

public static void applyBorderCss(com.vaadin.flow.dom.Element element,
 Border border)

Write the CSS representation of border onto element. Dispatches by runtime type across the JDK border hierarchy:

• LineBorder → border: Npx solid color (+ optional border-radius).
• EmptyBorder → padding.
• MatteBorder (color-only) → four per-side border-X longhands.
• BevelBorder / SoftBevelBorder → border: 2px inset|outset color.
• EtchedBorder → border: 2px groove|ridge color.
• CompoundBorder with EmptyBorder inner → outer border + inner's insets as padding. Other inner types WARN.
• TitledBorder → inner border (or 1px solid default) + data-emul-border-title attribute carrying the title text; pseudo-element CSS rule injected once per UI via ensureTitledBorderStyleInjected(UI).
• Any other Border (including custom user subclasses) → WARN.

clearBorderCss(Element) runs first so the previous border's keys can't linger.

border = null clears without writing — same semantics as Swing's setBorder(null).

borderFromCss

public static Border borderFromCss(com.vaadin.flow.dom.Element element)

Reconstruct the closest JDK Border from the CSS currently written on element. Reverse of applyBorderCss(Element, Border) — lossy per SD_border_css_lossy: custom Borders, TitledBorder, CompoundBorder with a non-EmptyBorder inner, and icon-backed MatteBorder can't round-trip.

Dispatch:

• No border keys, no padding → null.
• Padding only → EmptyBorder.
• Uniform border with solid style → LineBorder (picks up border-radius into roundedCorners).
• Uniform border with inset/outset → BevelBorder.
• Uniform border with groove/ridge → EtchedBorder.
• Mixed per-side widths/colors → MatteBorder.
• Border + padding → CompoundBorder of reconstructed outer + EmptyBorder inner.