> General Features of the proposed solution
Migration of Applications for Web Environment - A Practical Approach
Overview on Interfaces and development systems
The interface is the part of the system that enables a user to interact with it, sending and receiving information. Because of this the migration of systems to the Web environment inevitably requires necessarily the reengineering solutions to deal with the interface of the application. The study on the development of applications shows a continuous advancement in the solutions given to the projects of interface.
Initially the same set of instructions that comes to access of information and rules for business, also deals with issues related to the interaction with the user, through the provision of the interface. Modernly, with the continuous development of methods and technologies available, the process of developing systems is separated into distinct modules. This method is called "Development in layers," allowing that conventional applications can be divided into main components of access to data, business rules and user interface (EDWARDS, 1997 apud BELLIN, 2000, p. 15).
The advance of the proposed solution, or either, the division into components responsible for data, business and interface, enables that corporations, as a general rule, distribute the development of their projects in different teams, each responsible for a module, specialising in the solution of more specifics problems. Consequently appear at that point the professionals in the area of IT, "Information Technology", specialized in the development of interfaces for the end user.
When analyzing the history of the development of interfaces within the scope of Information Systems, it is possible to divide its progress in three generations (MARCHAL, 1998 apud BELLIN, 2000, p. 12).
The first is presented is the character generation, which makes use of platforms based on operating systems such as Unix and MsDos, taking as a means of access mainly terminals or workstations, and basically dealing with characters. Owing to restrictions resources, the interfaces built with these technologies do not allow a development with regard to the interaction between the user and the system, damaging then its use.
After further investigation, there is the need for an interface with standards that allow more functionality and greater interaction with users, giving rise to the emergence of the graphical interface. This second generation, with graphics features, called GUI, "Graphic User Interface", adds new elements to the interface, such as greater quantity and types of font, color, image, sound and ergonomics. Moreover, because the use of programming languages to object oriented, it has become easier to use windows, buttons, etc., providing a new vision to the concepts of design interface. Within the set of steps for the design of a system , the layer of interface will be an important factor, with the object of study of different branches of computing.
With the emergence of Internet a new environment and with it the third generation, which makes changes in the concepts and patterns of development of interfaces to the systems. Companies dealing with the development of the user interface, see in the Web technology, much of resources to a graphical interface, and they can be used in their internal systems. Moreover, the use of these resources, allows the equipment to access the systems have configuration simpler and lower cost. These factors ultimately providing a trend to the migration of information systems for the new Web technology.
Advantages, complexity and costs in the development of Interfaces
The evolution of the interface development to the graphical mode is an improvement for the user, facilitating its interaction with the system, making the operations more simple and intuitive. Moreover, in the view of the developer, although already dealing with best tools, occurs an increase in the complexity of developing applications. As a result of these factors, the development of interfaces becomes one of the most complex and expensive in the process of developing a system (NATAN, 1997 apud BELLIN, 2000, p. 13).
In the Web environment, the solutions, such as e-commerce and access to domestic banking systems, which distribute the information on the Internet, allow viewing by business, that the same resources can be used in corporate networks, thus resulting in the Intranets. The Intranet, which is the use of Web technology in the internal networks of businesses, contains very attractive features, not only by providing new resources but also to allow reduction of cost.
Below are listed some characteristics resulting from the use of resources Web in a application and it has direct impact on the costs of implementation and maintenance of interfaces:
- The workstations, which are computers used by users to have access to systems, do not require special configurations. Simply that the operating system has a browser, this feature available on most distributions of the market, paid or free.
- There are no necessary equipment for large processing power, in a general way, computers with profile for domestic use can be used.
- Allows the use of technology "thin-client", which are machines without disk drives, low energy consumption and with the operating system stored in volatile memory.
In addition to these features, the cost of users interfaces, are not restricted only to its development. The activities carried out by companies that deal with these issues, should also be considered its installation, upgrade and maintenance.
The interfaces are usually, implemented in the workstations, which are computers connected to networks of businesses, acquired and maintained by them. As far as lower are the requirements for these interfaces, conditions found in the Web environment, more simpler will be the equipment, thus minimizing the costs in their acquisition and maintenance.
The practice shows that much of the time spent by technicians in the area of IT, considering the stages of installation and maintenance, is used in the rehabilitation of stations, which for various reasons ceased to operate. When attempts to put these equipments back in operation, It is observed that the more mild the user interface, smaller is the time for their rehabilitation, thus generating lower cost with labor.
While the use of Web technology to developing interfaces in a way relevant reduce the cost of infrastructure and maintenance of machinery, the cost of development still remain high. Reducing these costs, using solutions that require a minimum of reengineering in legacy systems and techniques that are most adherent possible to applications become issues typically faced by the organizations.
The search for solutions to development of the user interface with Web technology, to implement standardization, make use of techniques for easy access to the largest possible number of users, allowing lower costs, mainly in the stages of development and maintenance, no leaving aside the question of quality, are elements that need to consolidate this article.
Besides the possibility of using current technology and in view that the technological advancement, better use of resources, the reduction of costs, among others, are permanently goals pursued by the companies, the use of Web resources for the development of users interfaces should certainly be considered.
It appears, however, that in view all the steps involved in the construction and provision of user interface, using Web resources, the costs in the development phase still have relatively high. When considering the solutions available on the market for development, paid or free, are invariably found the following technological resources, as explained in "Sistemas de Informação Baseados na Tecnologia Web: Um estudo sobre seu desenvolvimento", (FRATERNALI, 1999, apud ZANETI, 2003, p. 61).
Editors visual and managers of sites. - Tools based on the evolution of editors of Html pages, which does not give direct support to the development, primarily for applications based on the database, helping only with regard to the visual design of Web pages.
Tools of authorship of hypermedia to Web. - Exhibit the same limitations of the editors, not giving support to the development of structured applications, focusing mainly navigation and presentation and is generally used for applications where the information does not change often, such as publications in Cds and Kiosks.
Web-Dbpl Integrators - These integration of the Web and databases, allowing the production dynamics of pages from information previously stored in databases. Due to be focused on programming languages, these tools are limited in relation to development, with regard to the identification of the structure, navigation and submission of the application.
Web Form Editors - Used in migrating from client-server, usually an existing graphical interface for the Web technology. They allow the publication of forms-based programming and events, creating a repository of user interfaces, which will be subsequently attached to the application. They also support the process of management, testing and maintenance of these forms.
Tools multi-paradigm - They Integrate the different approaches and technologies for development of the previous options in a single solution. Post the same features already mentioned, but not brings new features to the development, remaining the limitations already mentioned.
Generators of application. - Provide complete coverage for all development activities, using techniques of software engineering in general ask for an reengineering systems more pronounced and that the existing solutions are tailored to the generator.
The use of these resources, combined or not, usually go through two alternatives described below, which can be used separately or together:
- Acquisition of ready solutions, which can be implemented in less time, but have significant cost of acquisition and are not always adhering to the existing information systems.
- Construction of tailormade solutions, usually executed by the company itself. This makes use of the re-engineering systems, demanding change of culture and more time for implementation.
Considering the above, although given the tools can, depending on specific situations, be given partially certain needs, nevertheless, does not realize that clear evidence pointing to the reduction of the costs of development.
> General Features of the proposed solution
Migration of Applications for Web Environment - A Practical Approach