Abstract: Methods and apparatus, including computer program products, implementing and using techniques for retrieving events from an event port. A request to retrieve a specified number of events from an event port to which completed events are posted by one or more event sources is received from a computer software application. It is determined whether the specified number of events is available at the event port. If the specified number of events is available at the event port, the specified number of events is retrieved from the event port and the retrieved events are returned to the requesting computer software application. If fewer events than the specified number of events are available at the event port, the request is placed in a request queue with requests to be processed at a later time and the request queue is ordered based on priorities of the requests in the request queue.

Abstract: Methods and apparatus, including computer program products, implementing and using techniques for alerting one or more computer software application threads waiting to retrieve events from an event port. An alert event generated by a computer software application is received at the event port. A state of the event port is changed to an alert state, if the event port is not already in an alert state, in response to receiving the alert event. One or more of the computer software application threads is notified about the alert state of the event port.