Synchronization in a Distributed Object System (Kurzbeitrag)

Abstract

We describe the integration of a synchronization protocol in a distributed object system, in particular focusing on autonomous objects. To ensure intra-object serializability a locking-based scheme exploiting the semantics of operations is used. In our system the decision if a lock can be granted or not can be made at the objects’ level. The objects’ autonomy then facilitates that the lock management can be done locally by the objects themselves, i.e., can be integrated into their behavior. The cooperation between a group of objects working on a common task is managed by control objects corresponding to transactions. These objects enforce a two-phase locking protocol, thereby achieving inter-object serializability. Objects execute operations on behalf of transactions and can autonomously react to the changes on its state these operations cause. The relationship between a transaction and the reactions it causes are incorporated into the system in a way similar to coupling modes as introduced in active database systems.