The article sets out a few key moments, which should be considered when developing software for terminals. Under a terminal in this document should be understood payment kiosks, self-service kiosks, internet access kiosks.

The User Interface

The system users mostly are not very much advanced in contemporary technologies. For over a number of years terminals have been equipped with touch screens. Owing to such screens, people feel at ease and can promptly select necessary items via the screen menu. In other words when developing a system we shall select a touch screen as the input and data display device. For simple systems, a 15-inch screen is quite enough. For a system with a more complex and advanced interface 17-inch displays would be a better choice.

Which Technology to Choose for UI

There are several options. The most common are Flash and HTML in a browser (browser in the full-screen mode or IE Active X). Flash + Celeron 1.7 GHz are enough for a payment terminal. However, for dynamic games like “one-handed bandit” such technologies are no good. Read the rest of this entry »

Authors: Renat Akhmerov, Alexey Kharlamov

Since the public introduction in August of 2006 the Google Web Toolkit (GWT) has gained significant momentum among web developer. The technology allows to build very interactive and responsive applications using convenient and very sophisticated tools as Eclipse, Maven and SVN. Moreover the GWT aims to build cross-browser applications by isolating platform specific quirks.

Our team has used Google Web Toolkit since the 1.1 release. While we are very happy with overall development experience we have found several performance limitations of the library. Actually, the limitations originate from restrictions inherited from the HTML layout algorithms and browsers implementations. In this article we will try to offer ways to workaround these limits by using more effective ways of HTML manipulations.

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Target setting

The main target is creating the system to provide service for working with video podcasts (a collection of video files which is distributed over the Internet using syndication feeds for playback on portable media players and personal computers) recorded by users and uploaded to the server. The access to the video should be provided on user’s request or via user’s connection to the broadcasting channel in real time. A number of users (privileged ones) should have the ability to create the podcasts (i.e. to upload digitized video of standard formats (AVI, MPEG2) recorded by personal video camera). All the users should have the ability to review the podcasts via web-browsers as a part of web-page.
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Developers who are on assignments building a social networking web site come across the issue that there isn’t any specific definition of this. There’s some functionality, which is considered as social network services. Moreover, the target audience has to be specifically defined without that, any social network would not progress even with any functionality at hands.

So which functionality can be considered as social networking? Surprisingly but over the third of such functionality is allocated in simple networks: registration, search, voting, user profiles, administration, SEO, forums. The source of social networks is the news sites with forums (the so called ‘portals’).

Web 2.0 gave an opportunity for closer virtual communications: personal blogs, comments, RSS, tags, interaction with friends. Primarily visitors and not the site admins as before do filling out with content here.

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Recently, Google Widget Toolkit attracted attention of web developers from all over the world. GWT is a great technology for AJAX development actually. It helps to get rid of many head-aches associated with cross-browser development, user interaction and development cycle.

The library provides unprecedented possibilities to build Web 2.0 applications with high level of interactivity. And there is a trap.

Often, the user interface of web-applications is simpler to build than desktop UIs due to two factors.First, the HTML/CSS ecosystem provides for a great number of tools to easily express designers vision.
And there is no need to build/run/debug cycle for the web-pages. Second, HTML provides for a significantly lower level of interactivity that is encapsulated by browser. So developers don’t need to debug each.

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Lately, I’ve been working on a geographically distributed clustered web system and got several ideas I would like to share. All of them are written by blood, sweat and pieces of lost dollars.

Don’t rely on stability
“Yes, this is obvious” – you may say. But I was knowing this from start the project also. However during deployment and preproduction testing the life has shown many new tricks to me. Building network system all conscious developers will introduce some retries/recovery routines. However, absence of components stability has many implicit consequences.

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One of the shortcomings of Wicket at this moment (versions 1.2 and 1.3) is non-Human-readable URL. In this article there are ways to avid that which are the results of the research Enterra made. The purpose of that was to get REST-style URL.
When using the solutions described in this article it needs to consider the difference between the versions of Wicket! They are described here at: http://cwiki.apache.org/WICKET/migrate-13.html

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When developing corporate-level business applications (Enterprise Scale) customers often requires implementing support for extensibility of the application object model not modifying the system source code. Use of extensible domain model allows for development of new functionality without additional effort and overheads:

1) the application will be used for a more lengthy period
2) the system workflow can be modified over time when changing external factors
3) “setting” the application to fit specifics of an enterprise where it has been deployed.
The most simple and cost effective way to achieve the required functionality would be implementing extensible business entities in an application with the support of custom fields.

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