Strategies for Using Queues and Groups

This section presents examples of several common uses of event queues and groups.

Default Queue Only

Use the default queue as the only event queue.

Note: Programs migrating from Rendezvous 5 (and earlier) can use this technique to emulate the event dispatch system of earlier releases.

Figure 16: Default Event Queue

Prioritize Queues within a Group

Dispatch the group, rather than individual queues. Assign queue priorities to reflect the relative priorities of their events (1 indicates the lowest, or last, priority; larger integers indicate higher priority).

This technique ensures that important events dispatch before less important events. For example, you can always dispatch a timer queue before inbound message queues, or give priority to messages with specific subjects.

Figure 17: Prioritize Event Queues in a Group

Selectively Suspend Dispatch

Remove selected queues from a group to suspend dispatch of their events. Even when a queue has been removed from its group, events continue to accumulate. Normal dispatch resumes when you add the queue back into the group.

Figure 18: Remove Event Queues from a Group to Suspend Dispatch