Customizable Concurrency Control for Persistent Java

We report on the issues raised when designing a customizable locking mechanism for Persistent Java, a type-safe, object-oriented, orthogonally persistent system based on the language Java. Customizable locking mechanisms are supported by locking capabilities. A locking capability is a bookkeeper of locks that automatically acquires locks with a customizable conflict detection mechanism. It implements the concepts of delegation of locks and ignorable conflicts, automatically keeps track of the dependencies created because of ignored conflicts, and supports the setting of user-defined notifications for conflicts that can’t be ignored. Locking capabilities are one of the primitive components of a more general framework that gives the ability to expert application programmers to implement new transaction behaviors in Java. The framework doesn’t change the Java language specification, and allows the use of any Java classes to implement the body of transactions without change to either their source or compiled form.