基于OCL的模型转换语言应用研究

模型转换语言是实施MDA的关键,在整个MDA体系中必须要有明确完备的转换语言.首先对模型转换语言的特性和现有的主要模型转换语言进行了简要的说明和分析,然后对对象约束语言（OCL）作为模型转换语言进行理论相关分析.在分析的基础上,提出了对对象约束语言进行扩展,最后提出了一个基于对象约束语言的模型转换框架.     

基于OCL的模型转换语言

首先对模型驱动以及与模型驱动开发密切相关的元模型和模型转换两个问题进行了简要的说明,并介绍了模型转换框架的相关概念,然后对对象约束语言（OCL）进行了相关的讨论,并对基于OCL的模型转换语言的元模型进行了说明.最后,在讨论的基础之上,提出了基于对象约束语言的模型转换语言,为形式化及自动化的模型转换描述与实现提供了一种有效的方法.     

形式化语言B与UML／OCL的比较

该文介绍了形式化方法中B语言和UML／OCL语言,从软件开发生命周期的角度对B语言和OCL语言进行了比较,归纳了这两种形式化语言的异同和各自的适用范围。     

OCL与Object-Z作为UML约束语言的分析比较

UML是目前广泛使用的标准的面向对象建模语言。为了提高建模的精确性，UML模型可以用对象约束语言OCL或者是用Object-Z规格说明语言加以补充说明。本文从多个方面分析比较了这两种语言的特点，并提出建模人员应充分利用这两种语言的特点，对系统进行精确的建模。     

对象约束语言及其在精化PIM中的应用

为了应用精确、完备的PIM自动进行模型转换、校验及编译,分析了OCL元模型与UML元模型间的关系,在此基础上对OCL在精确化平台无关模型(PIM)方面的应用进行了研究,指出OCL面临的挑战,并对OCL的研究方向提出了几点建议。对象约束语言OCL可以对模型中的元素进行约束和查询,可以在MOF的任意一层上定义模型语言,还可以通过各种方法定义模型的转换规则。     

Linux下Oracle的C语言访问方式分析

在Linux系统中C语言访问Oracle有多种方式,下面就对这些方式进行分析,并阐述OCI的技术方式针对性较强,并在研究中拓展为OCL方式,促进了C语言在Oracle中的应用效果。     

形式化语言B与UML/OCL的比较

该文介绍了形式化方法中B语言和UML/OCL语言,从软件开发生命周期的角度对B语言和OCL语言进行了比较,归纳了这两种形式化语言的异同和各自的适用范围。     

MujavaX:一个支持非均匀分布的变异生成系统

变异分析是一种广泛用来评估软件测试技术性能的方法.已有的变异分析技术通常将变异算子平均地应用于原始程序.由于现实程序中的故障分布往往具有群束的特征,采用平均分布的变异分析方法不能客观地评估软件测试技术的性能.前期研究工作中提出了非均匀分布的变异分析方法,采用实例研究验证了不同的故障分布对测试技术性能评估的影响.为了增强非均匀分布的变异分析方法的实用性,开发了支持非均匀分布的变异生成系统MujavaX,该系统是对广泛实践的Mujava工具的扩展与改进.采用一个实例系统验证了开发的MujavaX的正确性与可行性,实验结果表明该系统能够生成指定分布的非均匀变体集合.     

Linux下Oracle的C语言访问方式分析

在Linux系统中C语言访问Oracle有多种方式,下面就对这些方式进行分析,并阐述OCI的技术方式针对性较强,并在研究中拓展为OCL方式,促进了C语言在Oracle中的应用效果。     

基于代数式规范的变异测试方法的设计与实现

软件测试是软件工程中保证软件产品质量的重要组成部分.变异测试是一种衡量测试用例集完备性的测试策略,也被用于生成完备的测试用例集.为了提出一种基于代数式规范的新的变异测试方法,为此设计了12类针对代数式规范的变异操作符,对5个代数式规范进行了实验,并进行了结果分析.结果表明基于代数式规范的变异测试方法相比基于代码的传统变异测试方法,生成更少的变异体,也大幅度提升了变异测试的效率.     

Specification of temporal properties with OCL

The Object Constraint Language (OCL) is widely used to express static constraints on models and object-oriented systems. However, the notion of dynamic constraints, controlling the system behavior over time, has not been natively supported. Such dynamic constraints are necessary to handle temporal and real-time properties of systems.In this paper, we first add a temporal layer to the OCL language, based syntactically on Dwyer et al.'s specification patterns. We enrich it with formal scenario-based semantics and integrate it into the current Eclipse OCL plug-in. Second, we translate, with a compositional approach, OCL temporal properties into finite-state automata and we connect our framework to automatic test generators. This way, we create a bridge linking model driven engineering and usual formal methods.     

An experimental investigation of formality in UML-based development

The object constraint language (OCL) was introduced as part of the Unified Modeling Language (UML). Its main purpose is to make UML models more precise and unambiguous by providing a constraint language describing constraints that the UML diagrams alone do not convey, including class invariants, operation contracts, and statechart guard conditions. There is an ongoing debate regarding the usefulness of using OCL in UML-based development, questioning whether the additional effort and formality is worth the benefit. It is argued that natural language may be sufficient, and using OCL may not bring any tangible benefits. This debate is in fact similar to the discussion about the effectiveness of formal methods in software engineering, but in a much more specific context. This paper presents the results of two controlled experiments that investigate the impact of using OCL on three software engineering activities using UML analysis models: detection of model defects through inspections, comprehension of the system logic and functionality, and impact analysis of changes. The results show that, once past an initial learning curve, significant benefits can be obtained by using OCL in combination with UML analysis diagrams to form a precise UML analysis model. But, this result is however conditioned on providing substantial, thorough training to the experiment participants.     

Formal object-oriented development of a voting system test oracle

We report on the formal development of a test oracle for an electronic-voting system, detailing our approach which was based on a lightweight integration of Event-B, UML, and Java. This lightweight integration focuses on a coherent development process rather than on formal integration at the model/language level. We then briefly review alternative development approaches involving the use of JML and OCL. We conclude that the use of the OCL would offer few benefits, if any, in our formal development process.     

Refactoring object constraint language specifications

The object constraint language (OCL) plays an important role in the elaboration of precise models. Although OCL was designed to be both formal and simple, OCL specifications may be difficult to understand and evolve, particularly those containing complex or duplicated expressions. In this paper, we discuss how refactoring techniques can be applied in order to improve the understandability and maintainability of OCL specifications. In particular, we present several potentially bad constructions often found in OCL specifications and a collection of refactorings that can be applied to replace such constructions by better ones. We also briefly discuss how refactorings can be automated and how model regression testing can be used to increase our confidence that the semantics of an OCL specification has been preserved after manually performed refactorings.     

Software monitoring through formal specification animation

This paper presents a formal specification-based software monitoring approach that can dynamically and continuously monitor the behaviors of a target system and explicitly recognize undesirable behaviors in the implementation with respect to its formal specification. The key idea of our approach is in building a monitoring module that connects a specification animator with a program debugger. The requirements information about expected dynamic behaviors of the target system are gathered from the formal specification animator, while the actual behaviors of concrete implementations of the target system are obtained through the program debugger. Based on the information obtained from both sides, the judgement on the conformance of the concrete implementation with respect to the formal specification is made timely while the target system is running. Furthermore, the proposed formal specification-based software monitoring technique does not embed any instrumentation codes to the target system nor does it annotate the target system with any formal specifications. It can detect implementation errors in a real-time manner, and help the developers and users of the system to react to the problems before critical failure occurs.     

The KeY tool

KeY is a tool that provides facilities for formal specification and verification of programs within a commercial platform for UML based software development. Using the KeY tool, formal methods and object-oriented development techniques are applied in an integrated manner. Formal specification is performed using the Object Constraint Language (OCL), which is part of the UML standard. KeY provides support for the authoring and formal analysis of OCL constraints. The target language of KeY based development is Java Card DL, a proper subset of Java for smart card applications and embedded systems. KeY uses a dynamic logic for Java Card DL to express proof obligations, and provides a state-of-the-art theorem prover for interactive and automated verification. Apart from its integration into UML based software development, a characteristic feature of KeY is that formal specification and verification can be introduced incrementally.     

Integration of informal and formal development of object-oriented safety-critical software

The KeY system allows for the integrated informal and formal development of object-oriented Java software. In this paper we report on a major industrial case study involving safety-critical software for the computation of a particular kind of railway timetable used by train conductors. Our case study includes formal specification of requirements both on the analysis and the implementation level. Particular emphasis in our research is placed on the challenge to make authoring and maintenance of formal specifications easier. We demonstrate that the technique of specification patterns as implemented in KeY for the language OCL yields significant improvements.     

基于OCL文法的测试用例自动生成方法研究

随着软件测试技术的飞速发展,很多自动生成和执行测试用例的方法的技术已经发展起来。对于自动生成测试用例的约束的形式化定义也有很多方法,其中,对象约束语言(OCL)就是其中最具代表性的。OCL能够弥补UML模型的不足,精确地定义约束条件。本文将着重介绍一种从OCL文法解析到约束条件分离的方法的研究结果,通过与OCL文法比较,解析输入的OCL文本,提取OCL表达式,构建约束条件树,实现约束条件分离,最终实现测试用例集的自动生成。     

OCL for formal modelling of topological constraints involving regions with broad boundaries

Integrity constraints can control topological relations of objects in spatial databases. These constraints can be modelled using formal languages such as the spatial extension of the Object Constraint Language (Spatial OCL). This language allows the expression of topological integrity constraints involving crisp spatial objects but it does not support constraints involving spatial objects with vague shapes (e.g. forest stand, pollution zone, valley or lake). In this paper, we propose an extension of Spatial OCL based on (1) a geometric model for objects with vague shapes, and (2) an adverbial approach for modelling topological constraints involving regions with broad boundaries. This new language provides an easiness in the formal modelling of these complex constraints. Our approach has been implemented in a code generator. A case study is also presented in the paper in the field of agriculture spreading activities. AOCL _OVS takes account of the shape vagueness of spread parcel and improve spatial reasoning about them.