class CommonSession{
        public String session;
        public long createTime;
        public int timeout;

        public CommonCallback<Object> callback;
        public CommonCallback<String> timeoutCallback;
    }

    /**
     * 添加回调
     * @param sessionId 唯一标识
     * @param callback 回调
     * @param timeout 超时时间, 单位分钟
     */
    public void add(String sessionId, CommonCallback<Object> callback, CommonCallback<String> timeoutCallback,
                    Integer timeout) {<FILL_FUNCTION_BODY>

        CommonSession commonSession = new CommonSession();
        commonSession.session = sessionId;
        commonSession.callback = callback;
        commonSession.createTime = System.currentTimeMillis();
        if (timeoutCallback != null) {
            commonSession.timeoutCallback = timeoutCallback;
        }
        if (timeout != null) {
            commonSession.timeout = timeout;
        }
        callbackMap.put(sessionId, commonSession);
    
<no_super_class>