Developing New Presentations for Legacy Applications
Graphical User Interfaces with Minimal Effort
The T27 API for Java
Demands for more modern, user-friendly interfaces are driving Unisys ClearPath and A Series installations to consider re-implementing their mission-critical applications. However, re-writing the business rules from those legacy applications into new applications that provide a better user interface is a time-consuming operation fraught with risk. Upstanding  has developed a set of tools that simplifies the development of new user interfaces while reducing the risk and cost.
Mainframe applications have traditionally produced character-oriented screens to present customer information on, in the Unisys environment, T27 screens.

While acceptable at the time, the arrival of PC-based presentations has rendered traditional mainframe presentations of information inadequate. Upstanding , long dedicated to the premise of providing ClearPath/A Series users with solutions that enhance their existing applications, has developed two Application Programmatic Interfaces (APIs), SocketStations and the T27 API for Java, that simplify the burden of developing more user-friendly presentations of information. These APIs are structured to enable developers to concentrate their effort on the client and eliminate the need to make any changes to ClearPath/A Series programs. In both cases, any host application using a station-oriented interface, whether it is Remote File, COMS Direct Window, or MCS, is supported; COMS is not even required. Both of these APIs assume that TCP/IP is the networking protocol of choice. In this newsletter, the T27 API for Java is discussed.

Web-based Deliver for Legacy Applications

The Web-based user interface, whether for intranets or extranets, is an alternative to the client/server model. For organizations that favor a Web-based model, the client-resident T27 API for JavaTM offers some compelling advantages.
The most important advantage is the portability of the environment across different operating systems and different hardware platforms. The flexibility of providing access, not just on a Windows PC, but on less expensive 'thin' clients, or perhaps mobile Java-capable devices, is very appealing. Second, in contrast to the well-known distribution and management problems associated with client/server software, the Web-based model is inherently centralized.
In this model, Java code is developed and then downloaded to (or simply run on) the client to provide the user interface. The T27 API for JavaTM is a software module that is incorporated with Java code developed by the user, simplifying communication with the existing host application.

With the T27 API for JavaTM, the front-end developer accesses the legacy data by field, rather than having to deal with a raw data stream. As a result, developers can focus more on the presentation and less on the communication aspects.