Software Architect's Handbook

Loosely coupled architectures

When designing an evolutionary architecture, its components should be loosely coupled. In Chapter 6, Software Development Principles and Practices, we covered the importance of loosely coupled code. Coupling refers to the degree of dependency between components.

When modules are tightly coupled, it is more difficult to make changes. Changes to one component have a greater chance of affecting other components, increasing the total number of changes that have to be made. When you need to modify a tightly coupled system, more time and effort will be required for development and testing.

To ease the effort of making changes to the software system, dependencies between components should be minimized and all components ...