Abstract : Object-oriented languages provide insufficient answers regarding reuse of hierarchies of classes especially because mechanisms provided for separating application concerns are not sufficient. We propose to extend object-oriented languages, Java in the current implementation, to address this particular issue. The model, inspired by approaches dedicated to the separation of concerns, introduces a new concept called adapter. It enables to specify the composition protocol of a hierarchy of classes independently from the context of use. This composition protocol allows the programmer to benefit from the necessary guidance and controls when the adapter is customized to be integrated into applications.