流程违例处理的行为及分析

业务流程运行期间,外部或运行环境中的某些属性与流程设计时所设定的条件不一致时,将导致流程运行时的违例,违例处理方法涉及流程运行时违例的发现和处理。首先介绍了流程的违例及其分类;基于流程违例处理模式,使用CCS偶图对流程工作项级、案例级违例处理以及相关补偿处理进行分析和表述;在违例处理策略讨论的基础上,总结了违例处理模式的基本形式,并通过CCS偶图的动态特征分析了违例处理的动态行为。     

Web interface-driven cooperative exception handling in ADOME workflow management system

Exception handling in workflow management systems (WFMSs) is a very important problem since it is not possible to specify all possible outcomes and alternatives. Effective reuse of existing exception handlers can greatly help in dealing with workflow exceptions. On the other hand, cooperative support for user-driven computer supported resolution of unexpected exceptions and workflow evolution at run-time is vital for an adaptive WFMS. We have been developing ADOME-WFMS as a comprehensive framework in which the problem of workflow exception handling can be adequately addressed. In this article, we present an adaptive exception manager and its web-based interface for ADOME-WFMS with procedures for supporting the following: reuse of exception handlers, thorough and automated resolution of expected exceptions, effective management of Problem Solving Agents, cooperative exception handling, user-driven computer supported resolution of unexpected exceptions, and workflow evolution.     

Adaptive exception handling for scientific workflows

Scientific workflow systems often operate in highly unreliable, heterogeneous and dynamic environments, and have accordingly incorporated different fault tolerance techniques. We propose an exception‐handling mechanism, based on techniques adopted in programming languages, for modifying at run‐time the structure of a workflow. In contrast to other proposals that achieve the required flexibility by means of the infrastructure, our proposal expresses the exception‐handling mechanism within the workflow language—primarily as two exception‐handling patterns that are exclusively based on the Reference Nets‐within‐Nets formalism (a specific type of Petri nets). When an exception is detected, a workflow in our approach can be re‐written (replaced), based on the particular failure condition that has been detected. This enables workflow users to have better control and understanding of the behaviour of their workflow without having to be aware of the underlying infrastructure. Copyright © 2009 John Wiley & Sons, Ltd.     

工作流管理系统中的一种异常处理

目前，开发和运行企业过程的最好工具是工作流管理系统，对于企业这样复杂的应用系统，出现异常是非常频繁和正常的，但企业要求工作流管理系统不仅在正常情况下发挥作用，而且需要灵活地处理各种异常情况。文章设计了数字银行的电话收费业务的异常处理机制，使用JECA规则描述异常处理，同时采用基于CBR的异常处理机制提高系统的灵活性和柔性，增强系统处理异常的能力。     

工作流异常处理的形式描述

异常处理是工作流执行中要解决的主要问题之一，清楚地描述异常处理的过程是最终得到实现的基础。Petri-net对工作流的描述适合于对过程定义进行正确性验证和评价，但描述各种不同条件下的处理策略却很繁琐，采用了一种直观的描述方法对异常处理过程中的元素，即活动、异常处理策略以及处理措施进行了形式化描述，特别是对不同处理策略下的处理过程进行了描述。结合消息机制，分析了一个异常事件出现时，如何处理一个活动实例产生的中间数据，并对事务处理和异常处理的补偿策略进行了比较。描述方法为编码实现提供了很大的方便。     

Java异常处理策略研究

异常处理机制是程序设计语言的重要标志之一,在程序设计过程中用来处理程序运行中的异常。传统的程序设计语言里异常处理较为繁杂。Java是一种面向对象的程序设计语言,且引入了异常处理机制。合理完备的异常处理可以增强程序运行的可靠性、提高软件的健壮性,可以较为快速地确定错误的位置。文章分析了Java异常处理的逻辑,阐述了异常类、异常处理机制以及异常处理方法,提出了异常处理的一些策略。综合运用这些策略可以使编程人员编写出更加简洁、高效的程序代码。     

Exception handling refactorings: Directed by goals and driven by bug fixing

Exception handling design can improve robustness, which is an important quality attribute of software. However, exception handling design remains one of the less understood and considered parts in software development. In addition, like most software design problems, even if developers are requested to design with exception handling beforehand, it is very difficult to get the right design at the first shot. Therefore, improving exception handling design after software is constructed is necessary. This paper applies refactoring to incrementally improve exception handling design. We first establish four exception handling goals to stage the refactoring actions. Next, we introduce exception handling smells that hinder the achievement of the goals and propose exception handling refactorings to eliminate the smells. We suggest exception handling refactoring is best driven by bug fixing because it provides measurable quality improvement results that explicitly reveal the benefits of refactoring. We conduct a case study with the proposed refactorings on a real world banking application and provide a cost-effectiveness analysis. The result shows that our approach can effectively improve exception handling design, enhance software robustness, and save maintenance cost. Our approach simplifies the process of applying big exception handling refactoring by dividing the process into clearly defined intermediate milestones that are easily exercised and verified. The approach can be applied in general software development and in legacy system maintenance.     

一种快速测试Java异常处理机制的方法

异常处理机制能增强程序运行的可靠性，提高软件的健壮性，但异常处理代码本身可能存在错误．由于它的特殊性。采用与测试普通代码同样的方法对其进行测试，通常效率不高而且很难达到预期的效果．在分析了利用断言违背策略进行软件故障注入技术的基础上，提出了将Java异常处理机制的特殊结构同断言违背策略、程序变异技术相结合，可以有效地测试异常处理代码。并设计工具来支持这种故障注入方法．     

面向迁移工作流可靠执行的协同监控模型

当前跨机构的工作流管理中,对业务流程实施有效监控是保障其可靠执行的重要手段.然而,无论是传统的监控方法还是新近出现的针对移动个体的监督容错机制,均无法有效解决对类似迁移工作流这种多主体协调并发执行过程的异常监控以及协调恢复问题.首先给出迁移工作流执行框架,即一个业务流程由多个具有层次关系的迁移实例通过协商与协作而实现;在此基础上提出一种层次型协同监控模型(HCM3),模型根据执行同一工作流的不同迁移实例之间的组织层次关系,派遣不同的监控者实施监控,通过监控者之间的协调机制实现对异常状态在不同层次的诊断与处理,以保持全局状态的一致.模型能够实现监控的并发性和异常处理的层次性,在一定程度上避免了单点瓶颈,提高了工作流执行的可靠性.     

Adeptflex—Supporting Dynamic Changes of Workflows Without Losing Control

Today's workflow management systems (WFMS_s) are only applicable in a secure and safe manner if the business process (BP) to be supported is well-structured and there is no need for ad hoc deviations at run-time. As only few BPs are static in this sense, this significantly limits the applicability of current workflow (WF) technology. On the other hand, to support dynamic deviations from premodeled task sequences must not mean that the responsibility for the avoidance of consistency problems and run-time errors is now completely shifted to the (naive) end user. In this paper we present a formal foundation for the support of dynamic structural changes of running WF instances. Based upon a formal WF model (ADEPT), we define a complete and minimal set of change operations (ADEPT_flex) that support users in modifying the structure of a running WF, while maintaining its (structural) correctness and consistency. The correctness properties defined by ADEPT are used to determine whether a specific change can be applied to a given WF instance or not. If these properties are violated, the change is either rejected or the correctness must be restored by handling the exceptions resulting from the change. We discuss basic issues with respect to the management of changes and the undoing of temporary changes at the instance level. Recently we have started the design and implementation of ADEPT_workflow, the ADEPT workflow engine, which will make use of the change facilities presented in this paper.     

基于事务和Agent联邦的工作流异常处理机制

异常处理和恢复是工作流管理系统(workflow management system,WFMS)不可缺少的部分.在把工作流异常分为技能级异常、活动级异常和工作流级异常的基础上,结合工作流中活动的事务性,提出了基于事务的异常处理策略,并在基于Agent联邦中各Agent的合作性,提出了异常的检测方法和传递机制,提高了系统处理异常的灵活性.     

Java异常处理机制研究

异常处理机制是程序设计语言的主要特征,它为开发稳定的软件系统提供了有力的支持.文章对Java语言的异常处理机制以及异常类的层次进行了详细介绍,提出了Java异常处理策略.     

测试Java异常处理机制的方法

异常处理机制能增强程序运行的可靠性,提高软件的健壮性.然而,如果异常处理机制使用不当,会带来许多潜在的错误,因而很有必要对程序的异常处理结构进行测试.提出了一种识别被测程序中的所有异常变量"定义-使用"关系的方法,并使用一个异常的定义-捕获度量来计算异常定义-使用链的测试覆盖.最后设计了一种异常分析及测试的原型工具.     

Extended event–condition–action rules and fuzzy Petri nets based exception handling for workflow management

Exception handling plays a key role in dynamic workflow management that enables streamlined business processes. Handling application-specific exceptions is a knowledge-intensive process involving different decision-making strategies and a variety of knowledge, especially much fuzzy knowledge. Current efforts in workflow exception management are not adequate to support the knowledge-based exception handling. This paper proposes a hybrid exception handling approach based on two extended knowledge models, i.e., generalized fuzzy event–condition–action (GFECA) rule and typed fuzzy Petri net extended by process knowledge (TFPN-PK). The approach realizes integrated representation and reasoning of fuzzy and non-fuzzy knowledge as well as specific application domain knowledge and workflow process knowledge. In addition, it supports two handling strategies, i.e., direct decision and analysis-based decision, during exception management. The approach fills in the gaps in existing related researches, i.e., only providing the capability of direct exception handling and neglecting fuzzy knowledge. Based on TFPN-PK, a weighted fuzzy reasoning algorithm is designed to address the reasoning problem of uncertain goal propositions and known goal concepts by combining forward reasoning with backward reasoning and therefore to facilitate cause analysis and handling of workflow exceptions. A prototype system is developed to implement the proposed approach.     

一种异常处理机制的设计与实现

异常处理是一种用来检测异常并时其进行处理的技术。异常处理机制已作为现代程序设计语言的一个重要的特性被广泛地采纳,以增强系统运行的可靠性,提高软件的健壮性。对异常处理在程序语言的实现进行了一般性研究,分析比较几种异常处理机制及其实现方法,提出了一种新的异常处理机制的实现方法。     

Java虚拟机异常处理机制的设计与实现

异常处理机制是程序设计语言的重要特征之一,它为开发可靠性软件系统提供了强有力的支持,介绍了不同语言的异常处理机制,对Ｊａｖａ语言的异常处理机制进行了详细论述,最后结合国产开放系统平台ＣＯＳＩＸ虚拟机异常处理的设计,深入探讨了在解释才及时编译执行两种不同的情况下,异常处理设计与实现的关键技术。     

工作流管理系统异常处理的方法与层次

工作流技术在信息处理领域的应用越来越受到重视,但应用中环境和用户要求的不断发展和变化需要工作流管理系统具有灵活的处理能力,工作流系统的异常处理正是要解决这种不断要求的变化。文章介绍了工作流异常处理的应用范围,总结了不同的应用方法,从系统的角度提出了工作流未来的异常处理层次,并在研究可适应性工作流技术方面进行了探讨。     

基于补偿业务生成图的组合服务异常处理方法研究

为提高组合Web服务执行的一致性、可靠性,提出一种基于补偿业务生成图的组合服务异常处理方法.基于业务流程中任务间补偿依赖关系,讨论了补偿业务生成图的自动生成问题.重点讨论了补偿任务、补偿目标和服务转让应用模式,并相应地介绍了支持框架和相关技术.在此基础上设计了补偿依赖关系、补偿业务生成图的自动生成及组合服务执行过程中异常处理算法.当业务流程出现异常采取向前或向后恢复处理时,该方法在保证补偿实现的同时,兼顾补偿服务不存在或补偿服务代价过高的问题,提高了业务流程执行过程中的自动化水平和自适应能力.仿真结果证实,该方法保证了异常发生时组合服务执行的可靠性和一致性.     

C++程序中异常处理的分析与测试技术研究

异常处理机制是一种运行时错误通知机制，将程序的正常控制代码和错误处理代码分离．然而异常机制的引入使得程序控制信息变得更为复杂；且开发人员一般难以熟练使用它，导致程序中会潜伏许多异常错误．扩展已有的显式异常分析技术，对隐式异常也进行了全面的分析并提出了过程间（内）控制流图的构造方法，并以此为基础给出了一个C＋＋程序健壮性改进模型．同时还提出了针对异常的两种动态测试策略：基于约束求解的异常测试策略和统计结构性异常测试策略．最后实现了一个初步的异常分析与测试原型工具并进行了初步实验分析，其结果表明本文提出的分析与测试方法对程序质量有较大程度的提高．     

Java异常处理的设计原则

异常处理是程序设计中必须重点考虑的问题。在深入剖析Java语言的异常处理机制基础上,对Java异常处理提出了指导原则,从而可以提高程序的安全性和健壮性。