Tech Corner: Take a Serious Look at the Eclipse IDE
By Dan Nissen, Engineering Manager, Unisys Roseville

If you are like most OS 2200 developers, you’re seriously proficient in your language of choice, whether it be COBOL, C, PLUS, or maybe even Java. And, you’re no doubt very well-versed in the ins and outs of application development, build, test, and deployment in the ClearPath OS 2200 operating environment.

So, why should you care about an integrated development environment (IDE), such as Eclipse?

Because Eclipse is being shaped into an IDE that makes sense for OS 2200 development. We are building on the strong foundation of the open source Eclipse base product (and wide world of plug-ins) by adding in functionality that integrates and supports the tools OS 2200 developers depend upon and the common workflows they follow. Our goal for the ClearPath OS 2200 IDE for Eclipse is to enhance your development experience through the use of industry-standard tools – without forcing you to make changes that degrade productivity or deviate from your proven processes.

This Tech Corner is designed to give you a feel for what Eclipse looks like in an OS 2200 world. So please, take a few minutes to learn more about the ClearPath OS 2200 IDE for Eclipse. And then make your own decision about whether or not it makes sense for your organization.

Get a New Perspective(s)

Let’s start with a discussion of perspectives. In the Eclipse world, a perspective is the developer’s view into the many things on his or her “to do” list. If you’re a fan of multi-tasking, you’ll love perspectives!

The perspective is comprised of multiple windows in which various activities are performed, such as code edit, error checking, debugging, search, and so on. Most importantly, these windows are linked together so that an action in one can have an effect in another.

Take a look at the screen shot below, which shows a typical perspective for the OS 2200 Project Plug-in for a COBOL developer.

• On the left is the OS 2200 Explorer, which gives you a structured view of your project and the objects in it. What’s a project? Well, it’s simply Eclipse-speak for a collection of application source files, a mechanism to edit them, and a workfile that holds all the pieces you’re working on. It can contain all or just a portion of your application source code, for example. With just a click in the OS 2200 Explorer window, you can navigate to whatever object within the project you wish to view.
• In the center of the screen is the Editor view, which contains the section of code you’re currently working on. Note the tab at the top. You can have multiple tabs at once, each with its own section of code being edited.
• On the right is Outline view of the file you’re currently editing. In this case we’re editing a COBOL program, so the Outline view shows the major sections in the code and allows quick navigation to specific areas.
• At the bottom of the perspective is a catch-all window with many tabs showing everything from tasks and problems to bookmarks and errors. When a developer clicks on the error log tab and clicks on an error, the Editor window will open right to the line with the problem.

Pretty powerful stuff – don’t you think?

Enabling OS 2200 Development From the Eclipse IDE

Unisys provides a number of OS 2200-specific plug-ins for Eclipse that are designed to integrate typical OS 2200 development activities into this IDE. Today, the list of OS 2200-specific plug-ins includes:

• OS 2200 Project Plug-in (which you saw in the previous section)
• OS 2200 Java Application Integrator
• COBOL Editor
• C Editor
• PLUS Editor
• OS 2200 Debugging
• Telnet
• CMplus
• Logging

As you’ve probably guessed from their names, these plug-ins are what give the OS 2200 flavor to Eclipse.

The OS 2200 Project plug-in “knows’ how OS 2200 development works – how developers edit, what program files look like, the fact that builds need run streams, that Telnet is used for access and PADS is the debugger, and so on. The OS 2200 Project plug-in is a “traffic cop” that issues commands from the Eclipse environment to the OS 2200 operating environment, understands how to look at the responses, and knows what developers need to see.

The OS 2200 Project provides the mechanism for editing all pieces of your application, with various add-on, language-sensitive editors for COBOL and PLUS, as well as Java and C/C++. With a push of a button in the Eclipse IDE, developers can initiate the build process and review the results. This includes the ability to review compile errors with editor integration to make fixes very straightforward. Words cannot really do justice to the power of the ClearPath OS 2200 IDE for Eclipse, but the following screen shots provide several examples that we hope will inspire you to give Eclipse a try.

COBOL Auto-Completion
COBOL is known for being a particularly verbose programming language with lots of constructs to remember. The ClearPath OS 2200 IDE for Eclipse with the COBOL Editor provides an auto-completion capability that helps developers get to the right construct quickly. Simply type the beginning of a command, hit Ctrl-space, and the COBOL Editor lists out the available syntax choices. This concept is common to IDEs so it will be familiar to new hires and helps all programmers work faster and more accurately.

Detecting Build Errors
The ClearPath OS 2200 IDE for Eclipse integrates development activities on the PC with builds running within the OS 2200 operating environment. As illustrated in the screen shot below, compile errors are shown in the Problem tab at the bottom of the screen and the Editor view is positioned to the line where the error occurred. On the left in the Package Explorer, there’s a red circle with an X that indicates all items in the package that have errors to be reviewed and corrected. As the developer clicks on various package items, the Editor and Problems views change accordingly.

Integrated Debugging
OS 2200 developers are familiar with PADS, the Programmers’ Advanced Debugging System, which runs via a terminal interface under demand. The ClearPath OS 2200 IDE for Eclipse offers all the functionality of PADS with a much improved user interface. Through the Editor view, developers can watch steps as they are executed. There are also watch windows that show variables and values, Stack Frames, and execution window (Telnet session). And unlike a dumb terminal interface, with Eclipse developers can roll back to examine a response that scrolled off the screen. You can debug your TIP applications, as well as demand or batch runs. The ClearPath OS 2200 IDE for Eclipse takes care of all the groundwork needed to enable debug communication between the IDE and ClearPath mainframe.

Java Application Integrator
For development organizations that want to leverage existing OS 2200 assets into composite applications and/or in a service-oriented architecture (SOA), the Java Application Integrator plug-in is a critical tool. This module generates “wrapper classes” to use with Resource Adapters (RAs) – the connectors to OS 2200 DMS and BIS databases and TIP/HVTIP transactions. It allows you to quickly generate the standard code sequences needed for the RAs and allows you to build the method invocations easily. See our white paper, ClearPath OS 2200 IDE for Eclipse - Modern Development for the Mainstream Mainframe on eCommunity for more about this topic. To learn more about how one organization is using its OS 2200 transactions in an SOA, see the recent Georgia Technology Authority case study. The GTA project used the Eclipse IDE for development of bi-directional Web Services from existing COBOL transactions running under OS 2200.

Give Eclipse a Try

Getting started with the ClearPath OS 2200 IDE for Eclipse is very simple – download the software from the eCommunity. If your organization is already using Eclipse, then the OS 2200 plug-ins can be added to your existing environment. Otherwise, our Eclipse All-in-One package is the perfect start. It contains the base open source product, selected open source plug-ins, and Unisys modified and developed modules as noted earlier in this article. The All-in-One package has been integrated and tested by Unisys engineering, packaged and released as a part of the OS 2200 IOE, and is supported¹ via Unisys Support at no additional charge.

¹ Support statement: Unisys will make reasonable efforts to work with the Open Source community to resolve problems. Unisys developed content falls under normal support policies.