By default, Fuse MQ Enterprise uses store-based cursors for persistent messages and file-based cursors for non-persistent messages. You can, however, configure your destinations to use a specified cursor implementation by adding the appropriate policy entries into the destination's policy map.

You configure a destination's policy set using a destinationPolicy element. The destinationPolicy element is a wrapper for a policyMap element. The policyMap element is a wrapper for a policyEntries element. The policyEntries element is a wrapper for one or more policyEntry elements.

The cursor policies are entered as children to a policyEntry element. The configuration elements used to specify the type of destination you are configuring. Topics use cursors for both durable subscribers and transient subscribers, so it uses two sets of configuration elements. Queues only a single cursor and only require a single set of configuration elements.

Topics maintain a dispatch queue and a pending cursor for every consumer subscribed to the topic regardless of whether the subscription is durable or transient. You can configure the cursor implementation used by durable subscribers separately from the cursor implementation used by transient subscribers.

You configure the cursor implementation used by durable subscribers by adding PendingDurableSubscriberMessageStoragePolicy child element to the topic's policyEntry element. Table 6 describes the possible children of PendingDurableSubscriberMessageStoragePolicy.

You configure the cursor implementation used by transient subscribers by adding pendingSubscriberPolicy child element to the topic's policyEntry element. Table 7 describes the possible children of pendingSubscriberPolicy.

Example 12 shows a configuration snip-it that configures a topic to use VM cursors for its transient subscribers and file-based cursors for its durable subscribers.

<beans ... >
  <broker ... >
    ...
    <destinationPolicy>
      <policyMap>
        <policyEntries>
          <policyEntry topic="com.fusesource.>">
            ...
            <pendingSubscriberPolicy>
              <vmCursor />
            </pendingSubscriberPolicy>
            <PendingDurableSubscriberMessageStoragePolicy>
              <fileDurableSubscriberPolicy />
            </PendingDurableSubscriberMessageStoragePolicy>
            ...
          </policyEntry>
          ...
        </policyEntries>
      </policyMap>
    </destinationPolicy>
    ...
  </broker>
  ...
</beans>

Queues use a single pending cursor and dispatch queue. You configure the type of cursor to use by adding a pendingQueuePolicy element to the queue's policyEntry element. Table 8 describes the possible children elements of the pendingQueuePolicy element.

Example 13 shows a configuration snippet that configures a queue to use VM cursors.

<beans ... >
  <broker ... >
    ...
    <destinationPolicy>
      <policyMap>
        <policyEntries>
          <policyEntry queue="com.fusesource.>">
            ...
            <pendingQueuePolicy>
              <vmQueueCursor />
            </pendingQueuePolicy>
            ...
          </policyEntry>
          ...
        </policyEntries>
      </policyMap>
    </destinationPolicy>
    ...
  </broker>
  ...
</beans>