Architectural Mechanisms represent key aspects of the technical solution that need to be standardized across the project. Everyone on the project should handle these concepts in the same way and re-use the same mechanisms in their code.

Architectural Mechanisms are used to satisfy architecturally significant requirements. They often equate to technical services or framework components in the software and form the basis for standardizing the way that the software works. Therefore, they are an important element of the overall software architecture. The definition of architecture mechanisms also enable decisions on whether existing software components can be reused to provide the required behavior; or whether new software should be bought or built.

The key point to take on board when discussing architecture mechanisms is that the defining them is all about making choices about *what* technology will be used to satisfy architecturally significant requirements. It is not about producing detailed design up front. This is a common misunderstanding. The creation of detailed design and software that shows *how* specific mechanisms are satisfied is a development task.

The value in defining architecture mechanisms is that it

1. explicitly calls out aspects of the solution mechanics that are common across the system. This aids planning.
2. puts down markers for the developers to build those aspects of the system once and then re-use them. This reduces the workload.
3. promotes the development of a consistent set of services. This makes the system easier to maintain.

An Architectural Mechanism can have three states: Analysis, Design and Implementation. These categories reflect the maturity of the mechanism's description. The state changes as successive levels of detail are uncovered during the refinement of architecturally significant requirements into working software. The categories are summarized in the table that follows.

Be aware that these states are frequently referred to themselves as Analysis, Design and Implementation mechanisms. These are synonyms and merely represent the architecture mechanisms in different states of development. The transition from one state to another can often be obvious or intuitive. Therefore, it can be achieved in a matter of seconds. It can also require more considered analysis and design, thus take longer. The following diagram illustrates the transition of Architectural Mechanisms from one state to another.

State Machine for Architectural Mechanisms