摘要BPEL是Business Process Execution Language的缩写，是一种基于XML的语言，用来定义Web服务范围内的企业业务过程，BPEL实现了人类大规模编程(Programming-in-the-Large)的梦想。用BPEL书写的过程可以用标准化的方式控制Web服务（用XML文档表示）之间的交互，这些过程可以在任意平台或遵从BPEL说明书的任意产品上执行。BPEL控制流图是BPEL分析的基础，软件工程人员可以借助BPEL控制流图进行BPEL的控制依赖分析、数据依赖分析、测试、调试以及重构。64611

    BPEL使用<flow>来提供并发性。并发活动的同步用<link>表示。每一个<link>都关联一个变迁条件（transition condition）。当所有的<link>s取得了某种状态后，这个连接条件的值才能确定下来。如果这个连接条件是真，则活动可以被执行，反之如果连接条件为假，则该活动不能执行并且所有通过它的<link>均被置为假。这样的状态将一直向下传递直到遇到某个活动的变迁条件为真，此时目标活动才可以执行。这种技术称之为死路径消除。死路径消除语义使得WS-BPEL过程活动路径执行的有所不同。

本文通过对给定的BPEL文件进行解析建模，得到一个可为外部所使用的BPEL控制流图（CFG），并在控制流图的基础上进行了死路径消除工作。为了直观表示所生成的控制流图的结构，文中给出了几个控制流图结构样例。

毕业论文关键词：  服务组合，BPEL，控制流图，WSDL，死路径消除 

毕业设计说明书（论文）外文摘要

Title        The Generation of CFGs for BPEL Processes     

Abstract Business Process Execution Language (BPEL) is a XML-based language used to define enterprise business processes within Web services. BPEL is based on Web services in the sense that each of the business process involved is assumed to be implemented as a Web service. Processes written in BPEL can orchestrate interactions between Web services using XML documents in a standardized manner. These processes can be executed on any platform or product that complies with the BPEL specification. BPEL control flow graph is the basis of BPEL analysis, software engineers can make use of BPEL control flow graph BPEL control dependency analysis, data dependency analysis, testing, debugging and refactoring.

BPEL uses <flow> to provide concurrency and synchronization. Synchronization between concurrent activities is provided by means of <link>. Once all the incoming <link>s have get status (true or false), the join condition can be evaluated. If the join condition evaluates to be true, the activity is executed. Otherwise, the activity is not executed and all the status of its outgoing <link>s are set to false, this situation will propagate downstream until a true join condition of an activity reaches, then the activity can be executed. This approach is called “dead path elimination (DPE)”.

The DPE semantics make the execution of the WS-BPEL process different.

In this paper for any given BPEL file, we first obtain its model using our modeling approach upon which we generate a corresponding control flow graph for the file and based on BPEL control flow graph we carry out dead path elimination . In order to present the CFG clearly , we explore a Graphical sample for it.

Keywords  BPEL DOM  control flow graph(CFG)  WSDL  dead path elimination

1引言 1

1.1 研究背景1

1.2 论文的主要工作2

1.3 论文的组织结构2

2相关知识  3

2.1 Web服务  3

2.2 BPEL介绍4

2.3 死路径消除(DPE)  6

3　BPEL控制流关系分析  8