Technique to facilitate fast, error-free software design

Spanish researchers have created a new software model verification technique that permits the early detection of errors at any point during the modelling process — not just on completion, as is the case now. Their breakthrough has been published in The Journal of Object Technology.

Any building project requires the formulation of a series of initial plans prior to starting construction to serve as a basis and guide for the whole process. A similar procedure is followed in software development, with the inclusion of a specific step known as modelling.

Engineers use modelling to describe a software system from a specific perspective, such as the data it will use, its components or the way they expect it to function. Going back to the building project example, the plans would be the ‘models’, which can be used for guidance during the development stage, as well as for carrying out simulations and tests.

“The model type most frequently used is the UML (Unified Modeling Language) class diagram notation, which is used to describe the structure of a software system,” explained Professor Robert Clarisó, from the Universitat Oberta de Catalunya (UOC). The advantage of working with these models is that they are more abstract than source code, which contains a lot of specific details about the technology being used.

“Models can be more concise, easier to produce and understand,” Prof Clarisó said. As such, modelling would serve more as a preliminary step rather than an alternative to source code. The models make it easier to understand the system being developed and can also be used to generate certain implementation elements, automating the most repetitive parts of the programming process.

The role of verification tools

Engineers use verification tools to prevent errors that could affect the code itself and, therefore, the final implementation of the system. Prof Clarisó noted, “We need to ensure the models are correct in order to minimise possible errors in the software that could occur as a result.”

Prof Clarisó and colleagues have now come up with a new verification technique for UML/OCL models that solves a common problem: every time a designer makes a change — such as adding, deleting or modifying information — to the model it means that the whole system has to be reanalysed, which is the why verification is usually only carried out once a definitive model has been produced at the end of the process.

“Our article outlines the application of incremental methods of verification; that is, we make it easier to verify a model any time changes are made,” Prof Clarisó said. Rather than only being able to verify the model at the end of the process, as is currently the case, this permits it to be verified during construction, without having to start from scratch, which facilitates the early detection of errors.

This method is also innovative in regard to its use of certificates, the examples that illustrate the correct operation of the model. As explained by Prof Clarisó, “When we modify a model, having a new certificate would remove the need for its verification. It’s far less costly to adapt a certificate than it is to rerun the verification process.”

The study authors propose that, rather than verifying the new model, a certificate from the original model could be adapted to the new one. The biggest challenge they now face is integrating these techniques into existing software modelling tools and environments.

Image credit: ©stock.adobe.com/au/REDPIXEL

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