Design of Rich Internet Applications

Well design application has following features


1. Logical organisation

2. Responsiveness

3. Predictability

4. Scalability

5. Interoperability



Logical organisation

Applications that use the AJAX based technology uses interface component as displayed in web browser window. Organisation of components are very important in determining usability.

Logical organization of components to make an sensible look and feel is very important for user's navigation experience.

Selection of correct Graphical user Interface object for the specific task is important in construction of effective Rich Internet Applications. Rich Internet Application are more similar to the desktop applications while providing Internet access to websites. As a result graphical interface for rich internet application must be consistent . Different color schemes or font size may distract user and also creates the feeling of moving aways from the application. Adequate use of CSS to provide consistent look necessary. In Rich Internet Applications primary window is the web browser's window which act as a container for child widgets (Graphical Objects). Primary window can be divided into various section with help of various HTML techniques like iframe, textbox etc in order to provide the specific functionality

While considering about logical prospective of Rich Internet Application various structural organizations should be considered to make a user friendly web application. For example highly structured documents are more accessible and provide easy navigation experience than those that aren't . Rich Internet Applications should provide facility for disabled people . For example developers can use style-sheet to control font style and thus eliminating the font element which can cause issues in accessibility. Rich Internet Application should provide adequate measures for disabled people to access the application easily. For example web application should use alternative text for images and other graphics content so that text can be presented to users as synthesized speech, braille, or visually-displayed text. Each of these three mechanisms uses a different sense-- ears for synthesized speech, tactiles for braille, and eyes for visually-displayed text. As there are various type of disabilities a user can have as result Rich Internet Applications should not be hardware dependent. Web application pages should be usable by people without mice, with small screen, low resolution screen, black and white screens, no screens, with only voice or text output etc.


Responsiveness

Responsiveness is defined as “The software ability to keep up with users and not make them wait”.

REF : “Jeff Johnson in his book GUI BLOOPERS: Do's and Don't for software Developers and web Designers”.

It is very important factor for determining the user satisfaction, maximizing responsiveness can increase or improve Rich Internet Application usability and help ensure its success.

It is very important to let user know what the application is serving at the point of time so the user did not get confused. Adequate feedback from the application lets user know weather processing is in progress or an error has occurred.

While doing complex task user should have the ability to do other task in the respective application, that is application should provide the ability of multitasking

There are two type of responsiveness a application can be provided to the user.

1. Feedback
2. Technological responsiveness


Feedback

While process number one is performing its task for example sending data to the server, user should be given the facility to perform different task in the respective application for example doing some calculation, converting curries etc. Each and every process in the application should provide some kind of feedback to let user informed about the progress of the task.

There are different types feedback as discussed below a application can provide to user.

1. Pointer Feedback
2. Progress Animation


Pointer Feedback

In this type of feedback the shape of the pointer is usually changed but Rich Internet Application can also provide voice messages for disabled people or can provide various images as a sign of progression.

Progress Animation

In this type of feedback a progress bar is displayed to the user which displays the progression of the process in percentage with a long bar sliding toward to the end of dialog box.

Technological Responsiveness

Technological efficiency is also responsible for better responsiveness of the web application for example efficient use of heavy objects in web page. Fast downloading of web application because of their light content or objects.

In order to make web application more technologically responsive developers should consider the Internet speed of the normal user. For example use of bulky contents like heavy images in the web application can eat up all the bandwidth of the customer and for dial-up users it becomes the point of frustration.

Web 2.0 applications can contain objects which can be the services provided by the different applications therefore user interaction with different services provided by the application should not give the impression that they are dealing with different applications.

For example RSS which is an XML format of syndicating content, it is an easy way to help user to get the information of their choice on a single website instead of browsing many different websites.

Working Ahead

Lets take an example of web 2.0 based technology AJAX and an example of site which provide the facility of displaying maps of th location or places which customer wishes to see.

If the customer wishes to find out a place in brighton than Rich web client should show the map of brighton as well as load the map of sussex in which brighton is located in the background so that if customer wishes to search place inside sussex , application can respond quickly to the request of customer.

Predictability

Predictability includes various mental models of software in users mind. Users are used to various ways of dealing with desktop applications, and as rich we applications are more desktop application similar as a result developer should consider these ways, like for example if user pressed “save as” button from the menu, then he/she expects a dialog box to save he/her document.

And while developing rich web applications developer should consider consistences among graphical user interface. For example the GUI of pop-up menus, dialog boxes, button and various widgets etc should be consistent. Slight inconsistencies between the look and feel can frustrate user and can reduce productivity .

Scalability

Scalability refers to how easily and efficiently developer can enhance rich web application. As a result developer should consider the object oriented modal for designing application . While developing web2.0 based rich applications developer should have full understanding of application's architecture, .because it will be cost effective to company and provide less stress to the developer . For example if s problem is identified and get solved in the design phase then it will save many human hours of debugging and cost to the company in comparison to solving the problem later which can be catastrophic.

The most important point developer should consider while developing a scalable application id the he/she should avoid complexity of the system design, as maintaining a complex system in operates cost and time to the user.

Developer should carefully select the technology while developing a system. To much use of various technology can limit the scalability of the system.

Interoperability

As web 2.0 rich applications use mash-ups of various service provided by different vendors, interoperability among these services in the application is very important. User should not feel that he/she is interacting with different application while dealing with different services in the application.

This type of interoperability can be provided to the user with help of data exchange between different service of the application. User should be able to use this type of facility with the help of drag-and-drop or clipboard etc.

Developer should consider following points while providing interoperability in the rich application.

• Application should use platform independent file format while exchanging the data between different service provided by the application.
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• Developer should use standard protocol for data exchange between services provided by the application. For example developer can use XML which is platform independent and understandable by most of the browser
• Care full use of scripts to maintain interoperability should be done.

Prioritizing the user work

Rich Internet Applications are made up of micro contents from other web services while providing there own functionality as well. For example if a web application provides a document editing facility and displaying of current news (from www.bbc.co.uk) simultaneously then application should balance the resource allocation according to user priority, if a user want to edit a document and did not have enough resource due to new functionality then application should halt to news function temporarily to provide enough resource to document editing function.