Singleton与线程初始化

Question

我想创建一个以asynctask开头的单例连接。我如何getInstance并知道它何时完成连接（连接或超时）。 这是一个异步的回调接口，单例类需要执行它并存储连接。

过来this，真的不知道该怎么做。

public class ConnectAsync extends AsyncTask<String, String, Connection> {

    private ConnectionCallback callback;
    private Connection connection;

    public ConnectAsync(ConnectionCallback callback) {
        this.callback = callback;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }

    @Override
    protected Connection doInBackground(String... params) {

        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost(params[0]);
        factory.setUsername(params[1]);
        factory.setPassword(params[2]);
        factory.setConnectionTimeout(5000);
        //factory.setAutomaticRecoveryEnabled(true);
        //factory.setNetworkRecoveryInterval(5000);

        try {
            connection = factory.newConnection();
        } catch (IOException e) {
            LogUtil.e("Connection", null, "Connection timeout");
            return null;
        } 
        return connection;

    }

    @Override
    protected void onPostExecute(Connection result) {
        super.onPostExecute(result);
        if (callback != null)
            callback.onConnect(result);

    }

    public interface ConnectionCallback {
        public void onConnect(Connection result);
    }

}

来自服务

deviceWorker.connect(new ConnectionCallback() {

                    @Override
                    public void onConnect(Connection result) {
                        if (result != null && result.isOpen()) {
                            LogUtil.hecsLog(TAG, "DeviceWokers fully operational");
                        }

                    }
                });