public boolean url(String url, String pkglisturl,
                              DocErrorReporter reporter, boolean linkoffline) {
        this.linkoffline = linkoffline;
        String errMsg = composeExternPackageList(url, pkglisturl);
        if (errMsg != null) {
            reporter.printWarning(errMsg);
            return false;
        } else {
            return true;
        }
    }