The Software Architecture is the Glue for Variety and Integration

Whenever a software system consists of different parts – either how they are internally developed and structured, where they are located, when they were developed, which methodology or underlying concepts are used – the problem of integration of these different parts comes up. This chapter shows that the architecture of a software system is the right level to organize the integration and the architecture provides the essence of the glue for the integration. We give different examples, which show the glue for different situations either in development or in maintenance, in different application domains, using higher or low-level infrastructures, for integration within a system or between a system and its environment, or for a framework applying reuse for its major application components. The ideas are applicable also in other domains outside software development and in the context of model-driven development.