code: protected void defineFilter(Context ctx, String name,
        String classname, Map<String,String> parameters, String[] urls) {
  
      FilterHolder holder = new FilterHolder();
      holder.setName(name);
      holder.setClassName(classname);
      holder.setInitParameters(parameters);
      FilterMapping fmap = new FilterMapping();
      fmap.setPathSpecs(urls);
      fmap.setDispatches(Handler.ALL);
      fmap.setFilterName(name);
      ServletHandler handler = ctx.getServletHandler();
      handler.addFilter(holder, fmap);
    }
docs: Define a filter for a context and set up default url mappings.