Abstract: Locking is a traditional technique for concurrency control in distributed computing and databases systems by empowering the only user to update shared data objects during a certain time.Operation transformation is an innovative technique for consistency maintenance in real-time cooperative systems.Both techniques fail to resolve all the inconsistency problems.In this paper，we will demonstrate the complementary roles of locking and operation transformation in consistency maintenance.A user-customized locking approach is presented and integrated with operation transformation for consistency maintenance in fully-replicated and collaborative environment.The user-customized locking approach integrating operation transformation is considerably reliable，highly responsive，non-blocking.The user-customized granularity of locking can ensure highest concurrency.The approach can ensure generic consistency and context-based consistency.

Key words: real-time collaborative system, locking mechanism, operation transformation, consistency maintenance, concurrency control

摘要： 锁是一种用于分布计算和数据库系统的传统的并发控制方法，它通过将对共享对象的修改访问权在某一时间内授予唯一的访问者，以使对共享对象的访问得以串行化；操作转换方法是一种用于实时协同系统中一致性维护的方法。这两种方法均不能完全解决数据一致性问题。论述了锁机制和操作转换在一致性维护中的互补关系，提出了一种用户可定制的锁方法，并将该锁方法与操作转换结合起来应用于全复制式的协同环境中。用户可定制的锁机制集成操作转换方法具有可靠性高、响应速度快和非阻塞的特点；用户动态定制加锁粒度可以保证最大程度的并发性。该方法有效地解决了实时群件系统中一般的一致性问题和特定上下文的一致性问题。

关键词: 实时协同系统, 锁机制, 操作转换, 一致性维护, 并发控制