The UML has recently been extended by an Object Constraint Language (OCL). This formal language can be used for specifying constraints on a model in order to restrict possible system states. We present some examples for illustrating main concepts of OCL. Problems with the current deenition of OCL resulting from imprecise or ambiguous deenitions are investigated. A comparison of OCL with a langu...

The Object Constraint Language (OCL) as a part of the UML standard [1] is a formal language for defining constraints on UML models. We present a software platform for OCL tool support [2]. The platform is designed for openness and modularity, and is provided as open source. The goal of this platform is, for one thing, to enable practical experiments with various variants of OCL tool support, an...

The recent trend in software engineering to model-centered methodologies is an excellent opportunity for OCL to become a widely used specification language. If the focus of the development activities is shifted from implementation code to more abstract models then software developers need a formalism to provide a complete, unambiguous and consistent model at a very detailed level. OCL is curren...

As a continuation of the OCL workshop during the MODELS 2013 conference in October 2013, a number of OCL experts decided to meet in November 2013 in Aachen for two days to discuss possible short term improvements of OCL for an upcoming OMG meeting and to envision possible future long-term developments of the language. This paper is a sort of “minutes of the meeting” and intended to quickly info...

The use of explicit null and invalid values in OCL can lead to complex and hard-to-verify specifications. In addition, these values complicate the logic of OCL and of transformation languages that use OCL, making it difficult to provide effective verification support for these languages. We define an alternative technique for using OCL with UML and model transformations which avoids the use of ...

Abstract In March 2020, universities in China transitioned to online education response the COVID-19 pandemic and intensified focus on collaboration learning. However, little is known about impact of undertaking collaborative learning (OCL) student teachers’ views process their own teaching This qualitative study examined 18 experience OCL way it affected them as learners future teachers. The p...

At present, the OCL language includes two constants, null and invalid, to represent undefinedness. This effectively turns OCL into a four-valued logic. It makes also problematic its mapping to first-order logic and, as a consequence, hinders the use of first-order automated-reasoning tools for OCL reasoning. We address this problem and propose a solution, grounded on the same principles underly...

The Object Constraint Language (OCL) is often used for behavioral specification of software components. One current problem in specifying behavioral aspects comes from the fact that editing OCL constraints manually is time consuming and error-prone. To simplify constraint definition we propose to use specification patterns for which OCL constraints can be generated automatically. In this paper ...

Software testing is one activity for Quality Assurance (SQA). One way to test through Black box cases at design level. Since UML a de-facto language and of the most used now day. Therefore, there need black using behavioral diagrams. Object Constraint Language (OCL) formal write constraints on diagrams as it unambiguous. Although against robustness have been designed OCL expressions but no yet ...

The Object Constraint Language (OCL) is part of the Unified Modeling Language (UML) to specify restrictions on values of a given UML model. As part of the UML 2.0 standardization process, a proposal for the new version OCL 2.0 has recently been adopted by the Object Management Group. This proposal provides extensive semantic descriptions by both a metamodelbased as well as a formal mathematical...