A flexible object merging framework

Abstract

The need to merge different versions of an object to a common state arises in collaborative computing due to several reasons including optimistic concurrency control, asynchronous coupling, and absence of access control. We have developed a flexible object merging framework that allows definition of the merge policy based on the particular application and the context of the collaborative activity. It performs automatic, semi-automatic, and interactive merges, supports semanticsdeterrnined merges, operates on objects with arbitrary structure and semantics, and allows ftne-grained specification of merge policies. It is based on an existing collaborative applications framework and consists of a merge matrix, which defines merge functions and their parameters and allows definition of multiple merge policies, and a merge algorithm, which performs the merge based on the results computed by the merge functions, In conjunction with our framework we introduce a set of merge policies for several useful kinds of merges we have identified, This paper motivates the need for a general approach to merging, identifies some important merging issues, surveys previous research in merging, identifies a list of merge requirements, describes our merging framework and illustrates it with examples, and evaluates the iiamework with respect to the requirements and other research effotts in merging objects.