Book Image

WS-BPEL 2.0 for SOA Composite Applications with IBM WebSphere 7

Book Image

WS-BPEL 2.0 for SOA Composite Applications with IBM WebSphere 7

Overview of this book

Business Process Execution Language (BPEL, aka WS-BPEL) has become the de facto standard for orchestrating services in SOA composite applications. BPEL reduces the gap between business requirements and applications and allows better alignment between business processes and underlying IT architecture. BPEL is for SOA what SQL is for databases. Therefore learning BPEL is essential for the successful adoption of SOA or the development of composite applications. Although BPEL looks easy at first sight, it hides a lot of potential and has many interesting advanced features that you should get familiar with in order to maximize the value of SOA.This book provides a comprehensive and detailed coverage of BPEL. It covers basic and advanced features of BPEL 2.0 and provides several real-world examples. In addition to the BPEL specification, this book provides comprehensive coverage of BPEL support on IBM's WebSphere SOA platform including security, transactions, human workflow, process monitoring, automatic generation of BPEL from process models, dynamic processes, and more.The book starts with an introduction to BPEL, its role with regard to SOA, and the process-oriented approach to SOA. The authors give short descriptions of the most important SOA platforms and BPEL servers—the run-time environments for the execution of business processes specified in BPEL—and compare BPEL to other business process languages. The book then moves on to explain core concepts such as invoking services, synchronous and asynchronous processes, partner links, the role of WSDL, variables, flows, and more.Moving ahead you will become familiar with fault handling, transaction management and compensation handling, scopes, events and event handlers, and concurrent activities and links. The authors also discuss the business process lifecycle, the correlation of messages, dynamic partner links, abstract business processes, and mapping from BPMN to BPEL.The book discusses details of using BPEL with IBM WebSphere SOA platform. You will be able to develop BPEL and SCA composite applications, and demonstrate different approaches with the help of examples in this book. You will get exhaustive information on monitoring BPEL processes, and developing dashboards.The authors explain transformation of business process models in BPMN (using Business Modeler) to BPEL and how to achieve round-tripping. The book covers a complete BPM lifecycle from modeling through implementation, execution, monitoring, and optimization, and presents advanced real-world examples. In addition to standard BPEL it also covers IBM specific extensions on the WebSphere SOA platform.
Table of Contents (16 chapters)
WS-BPEL 2.0 for SOA Composite Applications with IBM WebSphere 7
Credits
Foreword
About the Authors
About the Reviewers
Preface

BPEL servers overview


BPEL servers provide a run-time environment for executing BPEL business processes. Today BPEL servers are usually part of the SOA platform, which in addition to the BPEL server includes other elements of a complete SOA environment: application server, ESB, registry and repository, human tasks support, process monitoring, BRMS (Rule Engine), and adapters. Often a development environment is also included and sometimes a process modeling tool is also available. Most advanced SOA platforms support the automatic translation of business models into executable BPEL processes.

Most SOA platforms have been developed on top of modern software platforms, particularly Java Enterprise Edition and Microsoft .NET. BPEL servers leverage Java Enterprise Edition or .NET application server environments, where they can make use of the services provided by application servers, such as security, transactions, scalability, integration with databases, components such as EJBs (Enterprise Java Beans) and COM+ (Component Object Model), messaging systems such as JMS (Java Message Service) or MSMQ (Microsoft Message Queue), and so on.

The most important commercial SOA platforms with BPEL servers are listed as follows:

Microsoft also provides an SOA platform, although Microsoft does not use the acronym SOA as often as the other suppliers. Microsoft's SOA is built around Windows Workflow Foundation, Windows Communication Foundation, and Microsoft BizTalk (process server). In contrast to most of the other vendors, Microsoft does not support BPEL natively (yet). Microsoft BizTalk at the time of writing still uses XLANG/s, the Microsoft proprietary orchestration language. However, it allows the import and export of BPEL.

An important supporter of SOA is SAP. SAP Enterprise Service-Oriented Architecture (Enterprise SOA) has been defined by SAP as an open architecture for adaptive business solutions. Enterprise SOA is enabled by the SAP NetWeaver platform. SAP has positioned Enterprise SOA to deliver the benefits offered by service-oriented architecture, including enabling both flexibility and business efficiency. Most of SAP products, such as mySAP ERP, mySAP CRM, and mySAP SRM, are built upon Enterprise SOA.

There are also a few open source implementations:

In the following chapters, we will use IBM WebSphere SOA platform, including WebSphere Process Server, WebSphere Integration Developer, and WebSphere Business Modeler. Please remember that BPEL is an open specification; therefore, it does not differ between the products. BPEL code is portable between different BPEL servers. This holds true as long as you are not using some vendor-specific extensions. Therefore, in the next chapters we will first look at standard BPEL. Then, we will look at how to use BPEL using IBM WebSphere.

The future of BPEL

OASIS has been responsible for the further development of BPEL since April 2003. An OASIS Technical Committee, called WSBPEL TC, has been formed for the development of a new BPEL version, called WS-BPEL 2.0. The technical committee, which supervises and influences further development of BPEL, has many new members. This ensures that BPEL will be extended with new features and also ensures continuity of development. The number of participants involved in BPEL shows that industry support is large and still increasing. More information on WSBPEL TC can be found at http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=wsbpel.