ABSTRACT Concurrency Control in Rule-Based Software Development Environments

This dissertation investigates the concurrency control problem in software development environ-ments (SDEs). The problem arises when multiple developers perfonn activities that concurrently access the project's components, stored as database objects. The interleaved execu-tion of the developers ' activities leads to interference if they access overlapping sets of objects concurrently. An SDE can ensure that activities never interfere by modeling their execution in tenns of atomic transactions and allowing only serializable schedules. This prevents cooperation, which requires some degree of interference between the activities of multiple developers. To allow cooperation, an SDE must be provided with semantic infonnation about development activities. In rule-based SDEs, the necessary infonnation is readily available in the set of rules that defmes the process model of a project. The rules are loaded into the SDE, which provides process-specific assistance through a rule chaining engine. A single user command might lead the chaining engine to initiate a rule chain. The concurrency control problem in rule-based SDEs manifests itself in tenns of interference between concurrent rule chains. We present a mechanism that extracts semantic infonnation from the process model to solve the concurrenc