A method for pattern application based on concrete solutions

Abstract

Patterns and pattern languages have become valuable tools in many domains for representing proven solutions to frequently recurring problems. However, the use of patterns presents some challenges in practice. For example, it is often difficult to find the right patterns for a problem at hand. In addition, the application of patterns often involves a lot of manual effort, since the abstraction of implementation details when writing the patterns means that pattern implementations cannot be systematically reused. As a result, although patterns provide proven knowledge for conceptual solutions, they always have to be manually transformed into concrete implementations when a pattern is used in a specific use case. In particular, the interaction of patterns in pattern languages, thus, leads to high manual effort when implementing complex use cases. Therefore, in this thesis an approach is presented which aims at facilitating the use of patterns in practice. The approach is based on the idea that implementations of patterns are kept available as Concrete Solutions that can be directly reused in the implementation of use cases. To this end, the EINSTEIN-Method provides a framework for systematically storing concrete solutions for their reuse. The method uses Pattern-based Design Models to model conceptual solutions, which can subsequently be transformed into concrete solutions in a semi-automated way. This involves supporting the refinement of abstract patterns via more technologically specific patterns towards concrete solutions. Based on a formalization of pattern languages as graphs, Pattern Graphs with connected Concrete Solutions are introduced, which enable the systematic reuse of concrete solutions. Since patterns are often used in combination to solve complex problems, an approach for automating the aggregation of concrete solutions using Aggregation Operators is presented. In addition, the principle of pattern languages is also projected to the space of concrete solutions and, thus, with Solution Languages an approach is presented that also supports the manual aggregation of concrete solutions to an overall solution. For the reuse of concrete solutions, an iterative IT-supported approach is presented that allows to replace patterns in design models with concrete solutions. Resulting Solution Models can then be aggregated to an overall solution using aggregation operators. For automating the aggregation of concrete solutions, Solution Algebras are introduced that allow mathematical structures to be defined over the set of concrete solutions. For automating the aggregation of concrete solutions, it is also shown how the concept of aggregation operators can be implemented as Solution Aggregation Programs. These allow solution models to be aggregated into overall solutions in a semi-automated manner controlled by the user. For the identification of potential aggregation steps in a solution model, an algorithm is presented that supports the user in the selection of concrete solutions to be aggregated in the solution model. For the transferability of the EINSTEIN-Method into different domains, a tool environment is conceptually described. The practical feasibility of the presented approaches as well as the tool environment is demonstrated by an overall architecture and various tool prototypes. Finally, the feasibility of the presented concepts is shown by means of validation scenarios in different domains.