Extending OCL with Null-References
by Achim D. Brucker, Matthias P. Krieger, and Burkhart Wolff
From its beginnings, OCL is based on a strict semantics for undefinedness, with the exception of the logical connectives of type Boolean that constitute a three-valued propositional logic. Recent versions of the OCL standard added a second exception element, which, similar to the null references in object-oriented programming languages, is given a non-strict semantics. Unfortunately, this extension has been done in an ad hoc manner, which results in several inconsistencies and contradictions.
In this paper, we present a consistent formal semantics (based on our HOL-OCL approach) that includes such a non-strict exception element. We discuss the possible consequences concerning class diagram semantics as well as deduction rules. The benefits of our approach for the specification-pragmatics of design level operation contracts are demonstrated with a small case-study.
Keywords: HOL-OCL, UML, OCL, null reference, formal semantics
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Please cite this article as follows:
Achim D. Brucker, Matthias P. Krieger, and Burkhart Wolff.
Extending OCL with Null-References.
In Models in Software Engineering. Lecture Notes in Computer Science (6002), pages 261-275, Springer-Verlag, 2009. Selected best papers from all satellite events of the MoDELS 2009 conference.
Keywords: HOL-OCL, UML, OCL, null reference, formal semantics
(article) (BibTeX) (Endnote) (RIS) (Word) (doi:10.1007/978-3-642-12261-3_25) (
| abstract | = | {From its beginnings, OCL is based on a strict semantics for undefinedness, with the exception of the logical connectives of type Boolean that constitute a three-valued propositional logic. Recent versions of the OCL standard added a second exception element, which, similar to the null references in object-oriented programming languages, is given a non-strict semantics. Unfortunately, this extension has been done in an ad hoc manner, which results in several inconsistencies and contradictions.\\\\In this paper, we present a consistent formal semantics (based on our HOL-OCL approach) that includes such a non-strict exception element. We discuss the possible consequences concerning class diagram semantics as well as deduction rules. The benefits of our approach for the specification-pragmatics of design level operation contracts are demonstrated with a small case-study.}, | |
| address | = | {Heidelberg}, | |
| author | = | {Achim D. Brucker and Matthias P. Krieger and Burkhart Wolff}, | |
| bibkey | = | {brucker.ea:ocl-null:2009}, | |
| booktitle | = | {Models in Software Engineering}, | |
| doi | = | {10.1007/978-3-642-12261-3_25}, | |
| editor | = | {Sudipto Gosh}, | |
| keywords | = | {HOL-OCL, UML, OCL, null reference, formal semantics}, | |
| language | = | {USenglish}, | |
| location | = | {Denver, Colorado, USA}, | |
| note | = | {Selected best papers from all satellite events of the MoDELS 2009 conference.}, | |
| number | = | {6002}, | |
| pages | = | {261--275}, | |
| = | {http://www.brucker.ch/bibliography/download/2009/brucker.ea-ocl-null-2009.pdf}, | ||
| publisher | = | {Springer-Verlag}, | |
| series | = | {Lecture Notes in Computer Science}, | |
| title | = | {Extending OCL with Null-References}, | |
| url | = | {http://www.brucker.ch/bibliography/abstract/brucker.ea-ocl-null-2009}, | |
| wsbooktitle | = | {The Pragmatics of OCL and Other Textual Specification Languages}, | |
| year | = | {2009}, |