Use of patterns in formal development: Systematic transition from problems to architectural designs

Abstract. We present a pattern-based software lifecycle and a method that sup-ports the systematic execution of that lifecycle. First, problem frames are used to develop a formal specification of the problem to be solved. In a second phase, architectural styles are used to construct an architectural specification of the soft-ware system to be developed. That specification forms the basis for fine-grained design and implementation. 1 Elaborating the software development process Experience has shown that problems and bugs in software systems take their source mainly in the early phases of the software development process1. Hence, a software development lifecycle that derives the design of the software directly from the require-ments and then passes on to the implementation cannot be regarded as satisfactory. The step between requirements and design is too large. An additional phase should be introduced between the requirements and the design. One idea that has been accepted for some time now is that some kind of specifica-tion should be set up on the basis of the requirements, so that the requirements ar