Business Process Execution Language for Web Services (BPEL, WS-BPEL, or BPEL4WS) is the new standard for defining business processes with composition of services. It is the cornerstone of Service Oriented Architecture (SOA). With its ability to define executable and abstract business processes it opens new doors in business process management and represents the top-down approach to the realization of SOA.
BPEL is supported by the majority of software vendors including Oracle, Microsoft, IBM, BEA, SAP, Hewlett-Packard, Siebel, and others. Most of them already have products that support BPEL; others will follow soon.
This book explains the BPEL standard, provides a step-by-step guide to designing and developing business processes in BPEL, defines the role of BPEL in SOA, and discusses how BPEL relates to the web services stack and to other standards. It also covers two important BPEL servers—the Oracle BPEL Process Manager and Microsoft BizTalk Server. The book presents the service-oriented approach to business process definition using web services, which enables us to develop loosely coupled solutions.
Chapter 1 provides a detailed introduction to BPEL and Service Oriented Architecture (SOA). It discusses business processes and their automation, explains the role of BPEL, web services, and Enterprise Service Buses (ESB) in SOA, provides insight into business process composition with BPEL, explains the most important features, compares BPEL to other specifications, provides an overview of BPEL servers, and discusses the future of BPEL.
Chapter 2 provides a detailed introduction to the Web Services Technology Stack. It discusses the important standards and specifications for using BPEL and implementing SOA with web services, such as WS-Security, WS-Addressing, WS-Coordination, WS-AtomicTransaction, WS-BusinessActivity, WS-Reliable Messaging, etc.
Chapter 3 discusses the composition of web services with BPEL. The chapter introduces the core concepts of BPEL and explains how to define synchronous and asynchronous business processes with BPEL. The reader gets familiar with BPEL process structure, partner links, sequential and parallel service invocation, variables, conditions, etc.
Chapter 4 goes deeper into the BPEL specification and covers advanced features for modeling complex business processes. Advanced activities, scopes, serialization, fault handing, compensations, event handling, correlation sets, concurrent activities and links, process lifecycle, and dynamic partner links are covered in detail.
Chapter 5 explains how to use the Oracle BPEL Process Manager for deploying and executing business processes defined in BPEL. It describes the server architecture, tools, features, and common approaches for managing and debugging BPEL processes. The chapter also looks at graphical development of BPEL processes using Oracle BPEL Designer for JDeveloper and for Eclipse.
Chapter 6 takes a detailed look at the advanced features of the Oracle BPEL Process Manager including extension functions, dynamic parallel flows, Web Services Invocation Framework, Java embedding, Notification service, Workflow service, Identity service, and Oracle BPEL Server APIs.
Chapter 7 discusses MS BizTalk Server 2004 and its support for BPEL. It explains how to develop business processes in BizTalk and export them to BPEL. It also explains how to import BPEL processes into BizTalk and how to use the Orchestration Designer tool to define processes graphically, and compares BizTalk and BPEL constructs.
Appendix A provides a syntax reference for BPEL version 1.1. The appendix covers standard BPEL activities and elements, functions, attributes, and faults.
To test the examples in Chapters 3, 4, 5, and 6, you need to have Oracle BPEL Process Manager 10g installed on your system (http://www.oracle.com/technology/products/ias/bpel/), and for Chapter 7 you need Microsoft BizTalk Server 2004 (http://www.microsoft.com/biztalk/).
In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.
There are three styles for code. Code words in text are shown as follows: “We can include other contexts through the use of the include directive.”
A block of code will be set as follows:
<operation name=”TravelApproval”>
<input message=”tns:TravelRequestMessage” />
<output message=”aln:TravelResponseMessage” />
<fault name=”fault” message=”tns:TravelFaultMessage” />
</operation>When we wish to draw your attention to a particular part of a code block, the relevant lines or items will be made bold:
<operation name=”TravelApproval”>
<input message=”tns:TravelRequestMessage” />
<output message=”aln:TravelResponseMessage” />
<fault name=”fault” message=”tns:TravelFaultMessage” />
</operation>Any command-line input and output is written as follows:
schemac Employee.wsdlNew terms and important words are introduced in a bold-type font. Words that you see on the screen, in menus or dialog boxes for example, appear in our text like this: “clicking the Next button moves you to the next screen”.
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