An Exception Handling Mechanism for the Concurrent Invocation Statement

Several concurrent programming languages and systems – e.g., MPI, .NET, and SR – provide mechanisms to facilitate communication between one process and a group of others. One such mechanism is SR’s concurrent invocation statement (co statement). It specifies a group of operation invocations and normally terminates when all of its invocations have completed. To make the co statement more flexible, it can specify code in the invoker to execute as each invocation completes or to terminate the entire co statement before all of its invocations have completed. We have added an SR-like co statement to JR. Unlike SR, JR provides exception handling mechanisms, which are integrated with Java’s exception handling mechanism. However, JR needs additional mechanisms to deal with sources of asynchrony. The co statement introduces additional such sources of asynchrony for the invocations it initiates. This paper describes the design and implementation of an exception handling mechanism for JR’s co statement.