// create filter & mapping in web.xml (if present)
new WriteCommandAction.Simple(modifiableRootModel.getProject()) {
protected void run() throws Throwable {
final WebFacet webFacet = strutsFacet.getWebFacet();
final ConfigFile configFile = webFacet.getWebXmlDescriptor();
if (configFile == null) return;
final XmlFile webXmlFile = configFile.getXmlFile();
final WebApp webApp = JamCommonUtil.getRootElement(webXmlFile, WebApp.class, null);
if (webApp == null) return;
if (!FileModificationService.getInstance().prepareFileForWrite(webXmlFile)) return;
final Filter strutsFilter = webApp.addFilter();