* 1 * A Catalogue of General-Purpose Software Design Patterns

Software design patterns describe proven solu-tions to recurring software design problems. Knowl-edge of these patterns increases designers ’ abilities, leads to cleaner and more easily maintained soft-ware, speeds up implementation and test, and helps programmers document and communicate their de-signs. This paper catalogues over 100 general-purpose design patterns. The organizing principle of the catalogue is the use of patterns, i.e., the problems they solve. Other considerations, such as whether a pattern is behavioral or structural, how it is imple-mented, or whether it is high or low level, are secon-dary, because these aspects are less important for a designer looking for a solution to a design problem. The catalogue collects general-purpose patterns from a variety of sources. It includes older patterns such as Module and Layers as well as modern, ob-ject-oriented patterns such as Observer and Visitor