Defining OCL constraints for the Proxy Design Pattern Profile

Profiles allow extend UML vocabulary and the design patterns define a common vocabulary for software designers, therefore it is possible to use profile to define a pattern vocabulary in UML. If profiles are used to represent patterns then it is not required to define a special notation neither a particular CASE tool for patterns (UML tool is used). Three mechanisms are in the profiles: stereotypes, tag values and constraints. Stereotypes extend the UML vocabulary and it is possible to associate to it tag values and constraints. When these elements are introduced in models; patterns can be clearly visualized, software developers improve communication and establish a common vocabulary. Also profiles allow add information to the model to transform it to other models. OCL (Object Constraint Language) constraints are semantic restrictions added to UML elements. This work shows a way in which OCL constraints are used to define semantic restrictions over stereotypes included in a profile of pattern. The definition of OCL constraints for proxy design pattern is shown as an example of our proposal. An interaction between users and UML tool is proposed for solving the loss generality when OCL constrains are imposed.