code: public void visit(final WebAppFilter webAppFilter) {
  		NullArgumentException.validateNotNull(webAppFilter, "Web app filter");
  		String filterName = webAppFilter.getFilterName();
  
  		if (filterName != null) {
  			//CHECKSTYLE:OFF
  			try {
  				webContainer.unregisterFilter(filterName);
  			} catch (Exception ignore) {
  				LOG.warn("Unregistration exception. Skipping.", ignore);
  			}
  			//CHECKSTYLE:ON
  		}
  	}
docs: Unregisters filter from web container.
  
  @throws NullArgumentException if filter is null
  @see WebAppVisitor#visit(WebAppFilter)