core/src/main/java/com/digitalpebble/stormcrawler/protocol/selenium/NavigationFilters.java
@SuppressWarnings("rawtypes")
    public static NavigationFilters fromConf(Map stormConf) {
        String configfile = ConfUtils.getString(stormConf,
                "navigationfilters.config.file");
        if (StringUtils.isNotBlank(configfile)) {
            try {
                return new NavigationFilters(stormConf, configfile);
            } catch (IOException e) {
                String message = "Exception caught while loading the NavigationFilters from "
                        + configfile;
                LOG.error(message);
                throw new RuntimeException(message, e);
            }
        }

        return NavigationFilters.emptyNavigationFilters;
    }
@SuppressWarnings("rawtypes")
    public static NavigationFilters fromConf(Map stormConf) {
        String configfile = ConfUtils.getString(stormConf,
                "navigationfilters.config.file");
        if (StringUtils.isNotBlank(configfile)) {
            try {
                return new NavigationFilters(stormConf, configfile);
            } catch (IOException e) {
                String message = "Exception caught while loading the NavigationFilters from "
                        + configfile;
                LOG.error(message);
                throw new RuntimeException(message, e);
            }
        }

        return NavigationFilters.emptyNavigationFilters;
    }
Loads and configure the NavigationFilters based on the storm config if
there is one otherwise returns an emptyNavigationFilters.