Introduction | Java & BAPI Technology for SAP

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This book is the bridge between what has been up until now two different areas of application development. The first area is development within the SAP environment, where the code is written in SAP's programming language, ABAP; the second area is development with one of the primary Internet development tools, Java programming and HTML (Hypertext Markup Language). In my experience, most programmers handle and stay current in only one of these areas, resulting in cumbersome solutions that could be performed simply if the two areas were melded.

In addition to covering the technical details of programming in Java, BAPIs (Business Application Programming Interfaces), and their integration within SAP, this book also covers the methodology that you can use to determine which development approach is best for solving a specific problem. The integration of the various modules within SAP-such as the employee or sales module-to other applications, and the ability to access SAP data are becoming more and more important as e-commerce within and between corporations increases.

Until about release 4.0 of SAP, integrating the ERP (Enterprise Resource Planning) systems with other solutions was not easy. Even development within SAP itself has been difficult, requiring thorough knowledge of how the different tables are related to one another in order to accomplish a specific business transaction or report. For example, consider a report that is supposed to display a list of materials. In addition to reading directly from the main table that contains materials (MARA), in earlier releases of SAP you must also access other tables for descriptions (MAKT), plant-specific information (MARC), and perhaps sales information (MVKE). You may also have to filter materials or views that are marked for deletion.

SAP has now cleared most of these hurdles with the introduction of the SAP Automation toolkit and the concept of BAPIs. Now, to get a list of materials, you simply perform one function module call, and the logic for the different tables, delete indicators, and so on is taken care of automatically.

SAP and other software manufacturers are beginning to develop the tools that allow users to access ERP systems with other development languages, such as Java, Visual Basic, and C++. While all of these languages can be used with SAP Automation software, this book concentrates on Java because it is currently the most popular programming language for Web development, and because it allows you to develop truly platform-independent code.

If you believe that an ERP system should provide all of the software needed to run a large corporation, you may wonder why anyone would want to use Java to access an SAP or other system. The answer goes back to the fundamentals of installing an ERP solution. The simple installation of a system such as SAP is not the end of system integration within a corporation, but merely the beginning. An SAP installation can be thought of as the primary building block in a complete data solution. After the ERP system is up and running, all primary business transactions are performed and all data is stored in one central location. Then the real synergy begins, with the ability to create reports and applications that will streamline business processes. Data that used to be stored in multiple databases can now be accessed through a single database.

Many clients that I have worked with have misunderstood this concept of developing and streamlining business software after the ERP solution has been installed. They believe that they will see instant cost savings and faster throughput times as soon as the ERP system is installed. What usually happens, however, is just the opposite. During the first year after a major ERP solution is introduced, costs for both support and training generally increase as people become familiar with the new environment. It's in the second year that clients begin to see ways to make their business methods more efficient; that's when the development really pays off and the cost savings are realized.

The SAP ERP system can be accessed through the standard SAP GUI (Graphical User Interface), through the Internet Transaction Server, or through custom applications. The last method is the main focus of this book. Through the use of BAPIs and Java, data and even entire business processes are accessible from this core data system. You can take information to a Web page directly from the SAP system, and because of the fundamentals of Java, the Web page or application can be run on any computer in the company. Java is platform independent, which reduces both development and ongoing maintenance costs for custom software.

This book also introduces other topics and technologies that are related to ERP software integration and Web development. Though the primary tool used in this book is the SAP Automation toolkit, one chapter covers tools such as IBM's VisualAge, and another is devoted to the ITS (Internet Transaction Server) technology from SAP. Other topics, such as ActiveX controls and COM (Component Object Model) compliant programming, are also discussed, in order to broaden your understanding of how the software development universe is evolving. This book also contains sections on HTML developments, along with many Internet URLs (Uniform Resource Locators) that will lead you to more current or more detailed information.

The basics of Java language make up the first part of the book. If you have never programmed in Java before, these chapters will teach you enough to develop fairly complex applications, and will give you a foundation for learning more about the Java language and its various classes. Readers who are familiar with Java may want to browse through this section as well. Java 2.0 introduces many new commands; for example, the first section of the book shows how to properly handle listening for events, such as buttons or field I/O (Input/Output) in Java 2.0. I spend a fair bit of time on the fundamentals of Java and object-oriented programming in general; with a good understanding of the fundamentals of Java, figuring out the more advanced concepts is relatively easy. The background material on object-oriented programming is also a good base for ABAP (Advanced Business Application Programming) programmers, as SAP is working to develop ABAP into a true object-oriented programming language.

The second section of this book focuses on how to integrate Java with SAP. This section covers the basics of integrating the SAP Automation toolkit so that you can develop applets or Java applications and access data within SAP. The examples start with step-by-step instructions for building simple projects, and then evolve into practical examples that allow you to see how the two areas, Java and SAP, can be used together. The Java classes that are used to integrate into SAP are discussed in detail so that even demanding applications can be written. Topics include connectivity through intranets, security, and exception handling.

SAP BAPIs

The final section of the book concerns SAP BAPIs, which are the main function blocks used in the integration of Java and other applications. BAPIs enable programmers who are not fully fluent in how the SAP database is set up to write programs that perform SAP business transactions or generate reports. This section also covers what BAPIs are, how to find them within SAP, and how to build your own custom BAPIs.

Finally, this book is meant to be an introduction to Java programming within the SAP environment. Many step-by-step examples help you fully reproduce and understand the concepts that are introduced. For example, an entire chapter is devoted to the installation and setup of the development environment. Usually, too much haste is made when getting started in new development areas, and counter-productive habits are learned early on. It is my philosophy that if people take the time to understand the basics well, then the advanced topics will come naturally.

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