Services Business & Technology Consulting Assessment to Implementation Health Care - HIPAA Legacy Systems Integration Systems Integration Infrastructure Support Information Integration Customer Relationship Management Document Management and Workfolw Supply Chain Solutions Business and Operations Support Systems		Legacy System Integration Approaches The six general approaches to obtaining access to legacy data from modern applications: Refacing, Repurposing, Restructuring, Re-engineering, Replacing and Multi-Tier Application Modeling. << return to Legacy Systems Integration Refacing Refacing is defined as replacing standard terminal emulation screens on a one-to-one basis with a graphical user interface (GUI). This approach is a non-invasive way to make a given host application blend in more seamlessly with GUI desktop environments without modifying the legacy host application. Its cost is low, and it can be achieved in very little time. However, the end result is only slightly different from the original application: the presentation is enhanced, but the logic and workflow of the application remain unchanged. Repurposing Capturing, encapsulating and exposing screen-based business logic from many screens and enterprise systems without modifying the legacy host application. Like refacing, repurposing is a non-invasive approach that results in an application that blends in with GUI desktop environments. It's slightly more costly and time-consuming than refacing, but ultimately yields much improved results. In contrast to refacing, the resulting application can be greatly different from the original application or applications involved. With repurposing, you can alter the workflow of the involved application or applications to better suit the business processes in your organization, streamlining those processes and enhancing productivity. Beyond simply integrating data from multiple host applications into a single presentation, repurposing may also involve building in new business logic for various purposes such as updating data sources, performing calculations, triggering events, and otherwise automating tasks in general. return to top ^ Restructuring Modifying an enterprise application to separate presentation and business logic. Restructuring an enterprise host application is more involved in terms of cost, time and complexity than either repurposing or refacing. As previously mentioned, in most legacy host applications, all three layers - Presentation, Business Logic, and Interoperability - are inextricably bound together. Accordingly, it's not possible to call application procedures bound in the Business Logic layer directly without passing through the Presentation layer and incurring its associated system resource overhead. An invasive approach, restructuring entails separating some of the Presentation, Business Logic and Interoperability layers in a legacy host application. Once that work is done, application procedures in the Business Logic layer can be wrapped with new interfaces and integrated into any number of new refacing or repurposing types of applications, completely bypassing the Presentation layer while preserving data integrity in the Interoperability layer. Ultimately, restructuring enables you to integrate only those application layers that you deem useful. For instance, perhaps there's an application procedure in the Business Logic layer of a given application that you'd like to leverage. Doing so commonly makes sense because the existing application logic is proven to work, and helps preserve data integrity in the Interoperability layer. Only through restructuring can you invoke the desired application procedure directly - without having to invoke any presentation logic - while helping to preserve data integrity. return to top ^ Re-engineering Re-engineering means scrapping the application and rebuilding the entire enterprise host application from scratch. If the application you need can only be achieved through re-engineering, it goes without saying that additional time, expense, and risk are also involved. Building from scratch, however, gives your organization exactly what it desires. Such applications are built to exact specifications, fully meeting your organization's business and technology needs. return to top ^ Replacing With application replacement, there's the opportunity to choose what operating platform you want the new application to run on, as opposed to being bound to the original. With an off-the-shelf product, you get the support of the application vendor, rather than having to support a homegrown application yourself. The key to success when replacing an application is to refine your business processes to match those of the new application and to ensure it integrates well within the existing application environment. return to top ^ Multi-Tier Application Modeling Recently, a further evolution of the screen-scraping concept has produced a major step forward. In this approach, a server is introduced as an intermediate tier residing between the client and the legacy applications. This enables the legacy screen datastreams to be modeled and managed on the server, fully isolating them from the new client applications; further, it enables increased manageability, maintainability, and scalability. The multi-tier approach has proven far superior to the older two-tier approach, especially for larger projects where ongoing growth and software maintainability are critical. For most organizations, the best approach to accessing legacy data is usually via multi-tier application modeling. It provides flexible, manageable, and scalable user access in real time and rapid time-to-market, within a reasonable budget. Ink2Web has both a proven methodology and a great deal of experience in each of these integration techniques, we can readily produce a fast and flexible solution with mission-critical reliability. Some of the key features of a complete multi-tier approach include: Support for a wide range of client front-ends, including Java, Windows APIs (such as ActiveX), and C-language libraries; Support for XML - Support for Application servers, including WebSphere and WebLogic; Ability to act as a legacy data source to standard end-user and development environments; Support for a wide range of back-end legacy hosts, including IBM mainframes presenting 3270 screens, IBM AS/400s presenting a 5250 interface, and a variety of UNIX, VMS, and other systems presenting a Telnet (VT100/220) interface; Management features and scalability enabling thousands of concurrent sessions; Automated tools for capturing screens and navigation, minimizing the amount of code to be written; and Intelligent design so that the client user interface, the database of screens and navigation, and the back-end data access are independent, optimizing code reuse.