The anthology of the finite state machine design patterns

No Finite State Machine (FSM) is an island. Every aspect of an FSM depends on its context, limitations of the programming language, system requirements, and many other factors. In more advanced systems, many independent FSMs cooperate together. The design describing their relationships is not an archipelago either, but rather a tightly coupled structure of classes or class hierarchies. This paper brings together many Object-Oriented FSM designs and compares them from the perspective of added flexibility as well as the cost associated with it. The final product is summary of the competitive advantages of different FSM designs in a specific set of conditions (e.g. problem domain, user expectations). This paper is intended to assist software engineers faced with the task of designing an optimal FSM implementation in a specific context. The uniform format of pattern summaries is intended to allow the designers to compare different patterns, based on their key characteristics – applicability, advantages, and disadvantages