For years, transactional protocols have been defined for particular application needs. Traditionally, when implementing a transaction service, a protocol is chosen and remains the same during the system execution. Nevertheless, the dynamic nature of nowadays application contexts (e.g., mobile, ad-hoc, peer-to-peer) and context variations (semantics-related aspects) motivates the need for transaction service adaptation. Next generation of transaction services should be adaptive or even better self-adaptive. This paper proposes CATE: (1) a component based architecture of standard 2PC-based protocols and (2) a Context-Aware Transaction sErvice. Self-adaptation of CATE is obtained by context awareness and component-based reconfiguration. This allows CATE to select the most appropriate protocol with respect to the execution context. We show that using CATE performs better than using only one commit protocol in a variable system and that the reconfiguration cost is negligible.