public HostFilter(String allow_file, String deny_file) {
        File allow = new File(allow_file);
        File deny = new File(deny_file);
        InputStream a_is = null;
        InputStream d_is = null;
        try {
            if (allow.canRead()) {
                a_is = new FileInputStream(allow);
            }
            if (deny.canRead()) {
                d_is = new FileInputStream(deny);
            }
        } catch (FileNotFoundException ex) {
            ex.printStackTrace();
        }
        initialize(a_is, d_is);
    }