A.8. Asynchronous Executions

In some scenarios, a translator will execute asynchronously and allow the executing thread to perform other work. To allow this, it is recommended that a DataNotAvailableException is thrown during a retrieval method, rather than explicitly waiting or sleeping for the results.

Since the execution (and the associated connection) is not closed until the work has completed, care must be taken if using asynchronous executions that hold a lot of state.

A positive retry delay is not a guarantee of when the translator will be polled next. If the DataNotAvailableException is consumed while the engine thinks more work can be performed or there are other shorter delays issued from other translators, then the plan may be queued again earlier than expected. You should throw a DataNotAvailableException again if your execution is not yet ready. Alternatively the DataNotAvailableException may be marked as strict, which does provide a guarantee that the Execution will not be called until the delay has expired or the given Date has been reached. Using the Date constructor makes the DataNotAvailableException automatically strict. Due to engine thread pool contention, platform time resolution, etc. a strict DataNotAvailableException is not a real-time guarantee of when the next poll for results will occur, only that it will not occur before then.