Book Image

Business Process Execution Language for Web Services

Book Image

Business Process Execution Language for Web Services

Overview of this book

Web services provide the basic technical platform required for application interoperability. They do not, however, provide higher level control, such as which web services need to be invoked, which operations should be called and in what sequence. Nor do they provide ways to describe the semantics of interfaces, the workflows, or e-business processes. BPEL is the missing link to assemble and integrate web services into a real business process BPEL4WS standardizes process automation between web services. This applies both within the enterprise, where BPEL4WS is used to integrate previously isolated systems, and between enterprises, where BPEL4WS enables easier and more effective integration with business partners. In providing a standard descriptive structure BPEL4WS enables enterprises to define their business processes during the design phase. Wider business benefits can flow from this through business process optimization, reengineering, and the selection of most appropriate processes . Supported by major vendorsó including BEA, Hewlett-Packard, IBM, Microsoft, Novell, Oracle, SAP, Sun, and othersó BPEL4WS is becoming the accepted standard for business process management. This book provides detailed coverage of BPEL4WS, its syntax, and where, and how, it is used. It begins with an overview of web services, showing both the foundation of, and need for, BPEL. The web services orchestration stack is explained, including standards such as WS-Security, WS-Coordination, WS-Transaction, WS-Addressing, and others. The BPEL language itself is explained in detail, with Code snippets and complete examples illustrating both its syntax and typical construction. Having covered BPEL itself, the book then goes on to show BPEL is used in context. by providing an overview of major BPEL4WS servers. It covers the Oracle BPEL Process Manager and Microsoft BizTalk Server 2004 in detail, and shows how to write BPEL4WS solutions using these servers.
Table of Contents (14 chapters)
Business Process Execution Language for Web Services
Credits
About the Authors
About the Reviewers
Preface
Index

Model Driven Approach: Generating BPEL from UML Activity Diagrams


Through the chapter we have seen that BPEL is a high-level language for specifying business processes. Because business processes are at such a high level, it is reasonable to think about defining process models using a modeling language and transforming these models to the BPEL code automatically. This is similar to the Model Driven Architecture (MDA) developed by the Object Management Group (OMG). The main objective of MDA is to raise the level of abstraction of development. Business processes are a perfect candidate for this approach.

The MDA approach is not to provide a simple graphical notation and a tool that enables developers to graphically build BPEL processes. The MDA approach is really about:

  • Defining a platform-independent model (PIM) of the business process

  • Defining exact rules that allow automatic mapping of the PIM to platform-specific models (PSM); these mappings can be done by a tool

In other words, this means...