General Features of the proposed solution
> A simple application of demonstration
< Overview on Interfaces and development systems
Migration of Applications for Web Environment - A Practical Approach
General Features of the proposed solution
This article aims to demonstrate what is possible with the use of Web resources, have access to new technologies inherent in both drop significantly the costs in the development and maintenance of user interfaces. To achieve the objectives, its continuation will be divided in five main phases, as Table 1 and in addition, in Appendix C, will be presented with a demonstration version of the system developed with a tool for commercial use, which uses the concepts and methods used in the system demonstration.
Table 1 - Sequence of activities
As shown in table 1, will be discussed first in general the roles within the proposed solution represented by the basic resources used for its implementation, namely, the Bash, Http, Html, Cgi, Css and Java Script.
In a second phase, will be presented a methodology for integrating and developing systems, briefly, just focusing on what it considers important to enable the development of user interfaces. For this will be used the concept of developing systems in layers, as described above, separating the data, rules of business and interface.In the same phase will be addressed the concept of integration of applications applied to internal layers of the system, or either, the use of a solution of single interface for the entire business.
In the third phase, will be developed an application simple of demonstration, based on character, but that has the already presented requirements in the second phase. Containing only a few options, will be a model with operating conditions, producing the basic conditions so that the user can interact with the system.
In the fourth phase, will be presented the migration of the application demonstrated for the Web environment, where to can observe the benefits of the methodology, with regard to development and aimed at the few requirements for its implementation, as well as the perception reduction of cost in the development phase. At this point will be presented the mechanism of access that effectively allows the provision of pages on the Web environment and view of the automatic generation of user interface, or the production of dynamic pages, which, after its use are totally discarded, and only needed at the time of communication with the users to the system.
In the fifth stage, simulating the process of maintaining the interface, caused by a new attribute inserted into an element of the application, will be presented a change in the system of demonstration, to take idea of the behavior of the methodology forward to a new reality.
Roles of resources Bash, Http, Html, Cgi, Css and Java Script
While not purpose of this article any detailing of the resources used, was included in its final, in Appendix A, an overview of them, in order to justify its use and allow better comparison with other equivalent. Continuing, will be presented soon the roles assigned to each of the resources in view of our goals.
The Bash will be used so we can write a simple application of demonstration, and this, specifically all the necessary services, such as dealing with the implementation of the interface, both in the character environment and in the generation version of Html pages in environment Web.Regarding Cgi, to be the means chosen to give every support to the pages of traffic between the Web server and the user's browser, in both directions.The Css, which take care of presentation aspects and positioning of elements on the pages and finally JavaScript loaded in the user browser that take care of the logic of page editing on the Web environment.In addition, is mentioned here the server of pages represented by Apache, mainly by its availability in both Linux and Windows platforms.Naturally for almost all the technology proposal there are other equally and even more current, such as Php, Java, Asp, etc. But the choice was guided in the use of what is considered the most basic possible, and specifically with the objective of achieving the largest possible number of users.
Systems Integration and Development Methodology
In view of the evolution of computing systems, it is observed that in its beginning the information was processed on systems independent and very often in different platforms, each taking care of their specifies area.With elapsing of the time, factors such as the dynamism of the organizations began to require the integration of information from the various systems in order to provide the most appropriate solutions for business. As most of the organizations used and still uses several types or generations of systems developed over the years, and these legacy systems have value for businesses, and adding to this scenario the advent of technologies based on the web, mainly as they have more direct relationship with the business, it became clear the need for integration between the environment and set of applications scattered among various departments of the organization.
When consideringthe characteristics of the solutions presented to the problems of integration, are found initially schemes point-to-point, establishing a channel of communication for each specific connection between systems, indicated by the arrows in Figure 1. In this method, also known as "integration type spaghetti" it is possible to understand that over time, and depending on the number of systems involved, it is confusing and difficult to maintain.
Figure 1 - Integration of systems point-to-point
Then appears the middleware schemes, which evolved in the middle of the decade from 90, to an approach known as EAI "Enterprise Application Integration" that emerged as an alternative to make possible the integration of enterprise applications with lower cost of maintenance and is synthesized as diagram in figure 2, where it is observed that the solution provides a common place, the Bus Integration, place where all systems involved sending and receiving their requests.
Figure 2 - Bus Integration
It is not part of the scope of this article issues involving the integration of systems, however it is possible to usethe template in Figure 2 above for the integration between Applications Modules and Interface of Operation and this similarity can be seen in the diagram of Figure 3. Similarly to what happens in the integration of systems, the solution comprises a single interface, which aims to meet the requests of the various modules of the system. Based on a scheme agreed modules communicate with the interface by sending and receiving their requests.
Figure 3 - Modules integrated through common interface
As already mentioned, with the continuous development of methods and technologies available, the process of developing systems is separated into distinct borders, called "Development in layers," allowing conventional applications can be divided, in general, in three main modules, as in figure 4:
Figure 4 - Development in layers
Building on a given application, with the focus modules that compose and specifically its communication with the user interface, in the conventional manner, is generally the scheme of Figure 5, where it notes that each module of the application you need interact with the user has its corresponding to run the service interface. This model, as we can provide, hinders the standardization and generates high cost of maintenance.
Figure 5 - An interface for each module
If on the other hand, adopted for a solution that has a goal to integrate, it is possible to agree on standards for communication between modules and interface, enabling all participants were relating to a single interface for care of your requests, as shown in Figure 6:
