WebSphere® MQ provides the ability to specify a filter when a subscription is made, but this can only refer to items in headers. IBM® Integration Bus can act as a content filtering provider for WebSphere MQ, and so allows extended filters to be specified by subscribers that can refer to elements in the body of publications.
When an application publishes on a topic string, where one or more subscribers have a selection string selecting on the content of the message, WebSphere MQ requests that the extended message selection provider parse the publication and inform WebSphere MQ whether the publication matches the selection criteria specified by each subscriber with a content filter.
If the extended message selection provider determines that the publication matches the subscriber's selection string, the message continues to be delivered to the subscriber.
If the extended message selection provider determines that the publication does not match, the message is not delivered to the subscriber. This might cause the WebSphere MQ MQPUT or MQPUT1 call to fail with reason code MQRC_PUBLICATION_FAILURE. If the extended message selection provider is unable to parse the publication, reason code MQRC_CONTENT_ERROR is returned and the MQPUT or MQPUT1 call fails.
If the extended message selection provider is unavailable or is unable to determine whether the subscriber should receive the publication, reason code MQRC_SELECTION_NOT_AVAILABLE is returned and theWebSphere MQ MQPUT or MQPUT1 call fails.
When a subscription is being created with a content filter and the extended message selection provider is not available, the WebSphere MQ MQSUB call fails with reason code MQRC_SELECTION_NOT_AVAILABLE. If a subscription with a content filter is being resumed and the extended message selection provider is not available, the WebSphere MQ MQSUB call returns a warning of MQRC_SELECTION_NOT_AVAILABLE, but the subscription is allowed to be resumed.
IBM Integration Bus extends the message selection support provided by WebSphere MQ. IBM Integration Bus does this by allowing ESQL statements rather than SQL92 statements, and filtering based on message content. See Content-based filtering using ESQL for details of the scope and exclusions of supported ESQL.
Root.MQRFH2.mcd.Msd='XML'
might
not work as you expect on z/OS.
Use the following syntax to search all MQRFH2 headers:FOR ANY Root.MQRFH2[] AS I (I.mcd.Msd='XML')
Read the following steps to see how to enable content-based filtering on IBM Integration Bus.