Detection of design pattern using Graph Isomorphism and Normalized Cross Correlation

Present day software engineering concept gives emphasis on the use of design patterns for developing software which are recurring in nature. Detection of design pattern is one of the emerging field of Software Reverse Engineering. In this work, an attempt has been made to present an approach for design pattern detection with the help of Graph Isomorphism and Normalized Cross Correlation techniques. In this study, system and design pattern are presented in the form of graphs. The Graph Isomorphism technique finds the pattern subgraph in the system graph and Normalized Cross Correlation provides a way to formulate the percentage existence of the design pattern in the system. An Eclipse Plug-in i.e., ObjectAid is used to extract Unified Modeling Language (UML) class diagrams as well as eXtensible Markup Language (XML) files from the software system and design patterns. An algorithm is proposed to identify relevant information from the XML files. Then Graph Isomorphism and Normalized Cross Correlation techniques are used to find the pattern subgraph and its percentage existence in the system. This approach has been applied on four open source software tools for the evaluation of five design patterns, such as Composite, Facade, Flyweight, State, and Template Method.