Roman Kisilenko

Servlet 3 introduces a new, more logical and easy to use API for doing programmatic authentication. It is a long-waited change by many developers. Before (without dealing with JAAS directly) the only choice was an old FORM authentication method, which is not flexible enough. It puts constraints on html markup making the method incompatible or difficult to use in some frameworks. Now you can easily use login(String username, String password) and logout() method pair declared on HttpServletRequest. It is definitely a nice step forward Read more…

Section 18.1 of EJB 3.1 specification requires a compliant container to provide “a reliable and transactional notification service for timed events”. In most cases developers will be satisfied with the implied level of reliability. However, it is necessary to understand some practical limitations so that appropriate measures can be taken and the timers can keep firing up as expected not only during development, but in production environment as well. Read more…

Sometimes it is useful to pass some state downside method invocation stack while keeping method definitions clean of extra parameters. Publications referenced below explain a few interesting ways you would probably like to try in order to achieve the desired effect. Read more…

In one of my recent posts I mentioned deltacloud, an open-source tool which have a great potential to make heterogeneous cloud deployments easier by providing developer an uniform, service provider- and language-independent API for cloud deployment management. In this post I’ll talk a bit about a real-life problem of configuring cloud node instances, which I’ve encountered when working with deltacloud, and a solution. Read more…

A few weeks ago I was working on an application capable sending faxes in an automated way. The platform is trixbox 2.6.2.3, equipped with a Digium TDM card. The faxing worked just fine on the installation “out of the box”, the fact everybody was happy with. But quite soon it became clear that the trixbox faxing module does not actually reports the status of the fax sent. Read more…

I would like to introduce an online-ping.info service, a collection of commonly used network diagnostic tools made available for use via browser. The sweet feature is an ability to retrieve and display SSH public host keys and fingerprints. Read more…

If you develop a cloud-enabled application, like quite many developers nowadays do, there likely will be a point in time when you’ll want to implement some features intended for managing your cloud deployment. In spite that cloud service providers usually give you nice APIs to develop your software against, it is still a kind of problem, because the APIs are proprietary and not standardized. See my previous blog post for problem statement. It is obvious that no proprietary API is an option for me.
The standardization between different cloud service providers is hardly possible at the moment, but hopefully there were some efforts in open-source community during last year, aimed on solving the above problem. Read more…

Recently I was involved in a project which can benefit from using cloud computing approach. The benefits are typical. They are the failover capability and ability to scale computing resources on demand. Working on a project design I found myself refreshing my vision on what the current cloud offerings available and how I would really like to use the cloud computing capabilities. Read more…

Below I’ll describe how to configure a bluetooth network access point (NAP) gateway using modern free open-source software, namely bluez 4 on Fedora 11. Configuration for other linux distros should be quite similar.
You can refer to a Personal Area Networking profile (PAN) for details on how bluetooth networking is organized. Important part is that network access point (NAP) provides some of the features of an ethernet bridge. Given that, it is quite logical that bluez NAP implementation connects bluetooth devices into a bridge, allowing you to use standard network tools to feed bluetooth devices with an access to your LAN or Internet. Read more…

The application was developed to deliver notifications and messages via phone, fax and email channels. Notification voice messages and text are generated using data from corporate systems. Answers entered by users via phone keypads can be stored in a database for further processing. Read more…