Exception handling in workflow management systems

Fault tolerance is a key requirement in process support systems (PSS), a class of distributed computing middleware encompassing applications such as workflow management systems and process centered software engineering environments. A PSS controls the flow of work between programs and users in networked environments based on a “metaprogram” (the process). The resulting applications are characterized by a high degree of distribution and a high degree of heterogeneity (properties that make fault tolerance both highly desirable and difficult to achieve). We present a solution for implementing more reliable processes by using exception handling, as it is used in programming languages, and atomicity, as it is known from the transaction concept in database management systems. We describe the mechanism incorporating both transactions and exceptions and present a validation technique allowing to assess the correctness of process specifications     

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。     

Testing homogeneous spreadsheet grids with the "what you see iswhat you test" methodology

Although there has been recent research into ways to design environments that enable end users to create their own programs, little attention has been given to helping these end users systematically test their programs. To help address this need in spreadsheet systems (the most widely used type of end-user programming language), we previously introduced a visual approach to systematically testing individual cells in spreadsheet systems. However, the previous approach did not scale well in the presence of largely homogeneous grids, which introduce problems somewhat analogous to the array-testing problems of imperative programs. We present two approaches to spreadsheet testing that explicitly support such grids. We present the algorithms, time complexities, and performance data comparing the two approaches. This is part of our continuing work to bring to end users at least some of the benefits of formalized notions of testing without requiring knowledge of testing beyond a naive level     

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。     

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.     

具有主动功能的程序设计语言及其实现技术

本文将提出一种主动程序设计语言的概念，它将改变一般程序设计语言只能用来编制被动执行的计算机程序的惯例，可使由该程序设计语言实现的系统具有主动提供各种服务的功能，使得诸如实时监控和报警功能（包括系统状态、性能、安全、故障或错误等的监控）、异常或错误的主动处理和自动恢复功能、系统瞬时状态或关键点状态的自动输出功能、适应多部门（或专家等）合作解题所需的通信和同步功能、演绎推理功能、灵活的实时处理能力、系     

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。     

Correct and Robust Programs

The design of programs which are both correct and robust is investigated. It is argued that the notion of an exception is a valuable tool for structuring the specification, design, verification, and modification of such programs. The syntax and semantics of a language with procedures and exception handling are presented. A deductive system is proposed for proving total correctness and robustness properties of programs written in this language. The system is both sound and complete. It supports proof modularization, in that it allows one to reason separately about fault-free and fault-tolerant system properties. Since the programming languages considered closely resembles CLU or Ada, the presented deductive system is easily adaptable for verifying total correctness and robustness properties of programs written in these, or similar, languages.     

Systems implementation languages and IRONMAN

The U.S. Department of Defense has recently issued a set of requirements, which it called IRONMAN, for the design of a programming language that it will use for embedded computer applications. To date four competing languages have been designed and, after considerable debate and scrutiny, these have been reduced to two. It is expected that the winning language will be selected during 1979. This report compares the IRONMAN requirements against the state-of-the-art in systems implementation language design in an attempt to see the extent to which IRONMAN can be met from existing technology. Particular emphasis is given to the areas of large-scale program structuring, parallel programming, exception handling and hardware interaction. Finally, Dijkstra's criticism of IRONMAN and the competing languages will be examined. It will be argued that he may be justified in doubting the viability of a language with such diverse features.     

Incremental programming language development

One of the well-known properties of software systems is that they are subject to changes. Incremental software development enables making such program changes in a non-destructive manner. In the area of programming language definition the language designer/implementer wants to include new language features incrementally as the programming language evolves. In the paper our approach to incremental programming language development is presented. The proposed approach has been successfully used in the development of real programming languages, which confirms feasibility in practice.     

Knowledge-based computer vision-integrated programming language anddata management system design

Properties that are needed in a language for programming computer vision tasks are described, and a new object-oriented programming language and data management system approach is suggested. An example from automatic pose estimation is used to illustrate the necessity for the properties in a language system, it is indicated where other languages and data management systems fail to provide these properties, and the type constructors used in the authors' system and features of the language semantics of their system are discussed     

基于程序分析的代码查询技术

策略描述语言是策略驱动的面向服务流程异常处理方法的基础和前提。针对目前已有策略语言在描述面向服务流程异常处理逻辑方面的不足,提出了一种新的面向服务流程异常处理的策略描述语言WS-Policy4BPEH。它在Web服务策略框架的基础上,扩展了ECA对规则执行影响的描述,定义了多种面向服务流程的异常处理动作模式,能够详细、准确地描述异常及异常处理方式、返回方式和传播方式。WS-Policy4BPEH采用XML作为元语言,因此具有良好的可扩展性。     

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.     

A practical method for specification and analysis of exceptionhandling-a Java/JVM case study

We provide a rigorous framework for language and platform independent design and analysis of exception handling mechanisms in modern programming languages and their implementations. To illustrate the practicality of the method we develop it for the exception handling mechanism of Java and show that its implementation on the Java Virtual Machine (JVM) Is correct. For this purpose we define precise abstract models for exception handling in Java and in the JVM and define a compilation scheme of Java to JVM code which allows us to prove that, in corresponding runs, Java and the JVM throw the same exceptions and with equivalent effect. Thus, the compilation scheme can, with reasonable confidence, be used as a standard reference for Java exception handling compilation     

Unveiling and taming liabilities of aspects in the presence of exceptions: A static analysis based approach

As aspects extend or replace existing functionality at specific join points in the code, their behavior may raise new exceptions, which can flow through the program execution in unexpected ways. Assuring the reliability of exception handling code in aspect-oriented (AO) systems is a challenging task. Testing the exception handling code is inherently difficult, since it is tricky to provoke all exceptions during tests, and the large number of different exceptions that can happen in a system may lead to the test-case explosion problem. Moreover, we have observed that some properties of AO programming (e.g., quantification, obliviousness) may conflict with characteristics of exception handling mechanisms, exacerbating existing problems (e.g., uncaught exceptions). The lack of verification approaches for exception handling code in AO systems stimulated the present work. This work presents a verification approach based on a static analysis tool, called SAFE, to check the reliability of exception handling code in AspectJ programs. We evaluated the effectiveness and feasibility of our approach in two complementary ways (i) by investigating if the SAFE tool is precise enough to uncover exception flow information and (ii) by applying the approach to three medium-sized ApectJ systems from different application domains.     

The history of Fortran I, II, and III

The article discusses attitudes about “automatic programming”, the economics of programming, and existing programming systems, all in the early 1950s. It describes the formation of the Fortran group, its knowledge of existing systems, its plans for Fortran, and the development of the language in 1954. It describes the development of the optimizing compiler for Fortran I, of various language manuals, and of Fortran II and III. It concludes with remarks about later developments and the impact of Fortran and its successors on programming today     

Agentsheets: a medium for creating domain-oriented visual languages

Customized visual representations enable end users to achieve their programming goals. Here, designers work with users to tailor visual programming languages to specific problem domains. We describe a design methodology and a tool for creating domain oriented, end user programming languages that effectively use visualization. We first describe a collaborative design methodology involving end users and designers. We then present Agentsheets, a tool for creating domain oriented visual programming languages, and illustrate how it supports collaborative design by examining experiences from a real language design project. Finally, we summarize the contributions of our approach and discuss its viability in industrial design projects     

实时异常处理技术的探讨

在分析现有异常处理技术的基础上，比较了在程序语言及操作系统中实现异常处理的优缺点，然后讨论了实时系统中异常处理的本质需求、必要需求及性能目标。为设计出适合于实时系统的异常处理机制，从异常的表示、关键度的管理等几个方面进行了讨论，为实时异常处理的设计提供了指导原则。最后对实时异常设计进行了总结，同时展望了该领域内的相关工作及发展方向进行。     

Twinkling lights and nested loops: distributed problem solving and spreadsheet development

In contrast to the common view of spreadsheets as “single-user” programs, we have found that spreadsheets offer surprisingly strong support for cooperative development of a wide variety of applications. Ethnographic interviews with spreadsheet users showed that nearly all of the spreadsheets used in the work environments studied were the result of collaborative work by people with different levels of programming and domain expertise. We describe how spreadsheet users cooperate in developing, debugging and using spreadsheets. We examine the properties of spreadsheet software that enable cooperation, arguing that: (1) the division of the spreadsheet into two distinct programming layers permits effective distribution of computational tasks across users with different levels of programming skill; and (2) the spreadsheet's strong visual format for structuring and presenting data supports sharing of domain knowledge among co-workers.