The construction of adaptive replicated systems, in which the replication control protocols can be replaced at runtime, requires to face with complex structural concerns that include: (i) the integration of replication control protocols with the application code, (ii) the the interchangeability of protocol variants, (iii) the observation and handling of events in a distributed system, and (iv) the consistency of the replication control mechanism. In this paper, we show a way to tackle that complexity with the help of Design Patterns and Aspect Oriented Programming (AOP).