Java 类org.w3c.dom.svg.SVGSymbolElement 实例源码

@Override
public SVGElement getViewportElement() {
    if (getParentNode() == ownerDoc) {
        return null;
    }
    Node parent = getParentNode();
    while (parent != null && !(parent instanceof SVGSVGElement || parent instanceof SVGSymbolElement)) {
        parent = parent.getParentNode();
    }
    return (SVGElement) parent;
}