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Using wild cards

Metatopics describing subscribers include information about wild card subscriptions. This is an exception to the rule that publications should not include wild cards in their topics.

In subscriptions to metatopics, wild cards can be used in the usual way. For example, if the metatopic 'MQ/S/QM1/Publishers/S

*' is specified, this matches 'MQ/S/QM1/Publishers/Summary' plus all the 'MQ/S/QM1/Publishers/Summary/Topic' metatopics (one for each topic registered implicitly or explicitly for publishers, except those published anonymously), and the broker sends this number of retained Publish messages as a result.

If the metatopic 'MQ/S/QM1/Subscribers/S

*' is specified, the resultant messages show all the topics registered for subscribers (except those registered anonymously), including wildcard subscriptions. (The wildcard characters in metatopics match only wildcard subscriptions.)

A wildcard subscription of the form '

*' gives all topics on a stream except the metatopics. You need to specify at least the first five characters ('MQ/S/') to receive publications about metatopics.

On WebSphere MQ for UNIX systems, we need to prevent the shell from interpreting the meaning of special characters, for example: *. Depending on the shell you are using, you might have to enclose the wildcard characters in single quotation marks or double quotation marks, or use a backslash.

 

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