class JwtSessionStateFactory implements SessionStateFactory {
    private static JwtSessionStateFactory instance;

    public static JwtSessionStateFactory getInstance() {<FILL_FUNCTION_BODY>}

    private JwtSessionStateFactory() {
        String signKey0 = SessionProp.session_jwt_secret;
        if (Utils.isNotEmpty(signKey0)) {
            signKey = signKey0;
        }
    }


    private String signKey = "DHPjbM5QczZ2cysd4gpDbG/4SnuwzWX3sA1i6AXiAbo=";

    /**
     * 获取签名Key
     * */
    public String signKey() {
        return signKey;
    }

    /**
     * 设置签名Key
     * */
    public void signKeySet(String key) {
        signKey = key;
    }


    public static final int SESSION_STATE_PRIORITY = 2;

    /**
     * 优先级
     * */
    @Override
    public int priority() {
        return SESSION_STATE_PRIORITY;
    }


    /**
     * 创建会话状态
     * */
    @Override
    public SessionState create(Context ctx) {
        return new JwtSessionState(ctx);
    }
}

        if (instance == null) {
            instance = new JwtSessionStateFactory();
        }

        return instance;
    
<no_super_class>