Java 如何检查InputStream是否正在发送数据？（与GSON合作）

我没有在StackOverflow上找到这个问题，或者我用松散的关键字搜索

我通常在互联网上获取JSON文件的InputSteam，这是我的主要功能：

    static HttpGet getRequest;
    static HttpResponse getResponse;
    public static InputStream retrieveStream(String url, int timeout) {

getRequest = null;
getResponse = null;

HttpParams httpParameters = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(httpParameters, timeout);
HttpConnectionParams.setSoTimeout(httpParameters, timeout);
DefaultHttpClient client = new DefaultHttpClient(httpParameters);

getRequest = new HttpGet(url);

try {

    getResponse = client.execute(getRequest);

    final int statusCode = getResponse.getStatusLine().getStatusCode();

    if (statusCode != HttpStatus.SC_OK) {
        Log.w("ERROR", "Error " + statusCode + " for URL " + url);
        return null;
    }

    HttpEntity getResponseEntity = getResponse.getEntity();

    return getResponseEntity.getContent();

} catch (IOException e) {
    getRequest.abort();
    Log.w("ERROR", "Error for URL " + url, e);
} catch (Exception e) {
    getRequest.abort();
    Log.w("ERROR", "Error for URL " + url, e);
}

return null;
    }

为了避免出现错误或允许用户取消请求，因为Internet已打开但运行不正常，我想在我的应用程序未接收数据且未完成时设置计数器。我知道怎么做计数器，但是，我怎么能做那种类型的“监听器”

我用于继续此操作（始终异步）：

提前谢谢

            InputStream source = f.retrieveStream(params[0]);
        Gson gson = new Gson();
        Reader reader = new InputStreamReader(source);

        response = gson.fromJson(reader, Usuario.class);