code: protected synchronized void bindFilterConfiguration(final FilterConfiguration config) {
          if (filterConfigurations == null) {
              filterConfigurations = new ArrayList<>();
          }
          filterConfigurations.add(config);
          String key = config.getName();
          ResourceFilter filter = config.getFilter();
          if (StringUtils.isNotBlank(key) && filter != null) {
              nodeFilters.put(key, buildTreeFilter(filter));
          }
      }
docs: for each configured filter in the OSGi configuration
  a tree filter is added to the filter set
  
  @param config the OSGi filter configuration object