Visualizing the design pattern interaction roles

Designing software involves thinking about the solution for a design problem. Some of the ideas of design solution are captured in the form of descriptions and structures in design pattern. However, there is not much visual aid on the behaviour of a design pattern in a visual design modeling tool. Currently it is difficult to determine the design pattern roles and the interaction variants of a design pattern in an UML diagram as the design pattern information is not represented. This paper proposes a method to define and visualize the pattern roles and its interaction variants by extending the UML sequence diagram via UML Profile. An illustration of the usage of the extension is then shown for the observer design pattern. The benefit of the extension enables tool support on cataloging and retrieval of design patterns structural, behavioral information and variants in a visual design modeling tool.