Architecting in the context of variability has become a real need in nowadays software development. Modern software systems and their architecture must adapt dynamically to events coming from the environment (e.g., workload requested by users, changes in functionality) and the execution platform (e.g., resources availability). Component-based architectures have shown to be very suited for self-adaptation purposes, not only because of their intrinsic characteristics like reusability and modularity, but also as virtue of their dynamical reconfiguration capabilities. The issue, nevertheless, remains that adaptation behaviors are generally conceived by means of fine-grained reconfiguration actions from the very initial configurations. This way, besides the complexity in managing large-sized architectures, the space of reachable configurations is not know in advance, which prevents ensuring well-mastered adaptive behaviours. This paper presents Ctrl-F, a domain-specific language whose objective is to provide high-level support for describing adaptation behaviours and policies in component-based architectures. The proposed language lies on synchronous reactive programming, which means that it benefits of an entire environment and formal tooling allowing for the verification and control of reconfigurations. We show the applicability of Ctrl-F by first integrating it to FraSCAti, a Service Component Architecture middleware platform, and then by applying it to Znn.com, a well known self-adaptive case study.