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Type NEW
Priority LOW
Topic XmlBlaster has a plugin interface to generically specify a query

As a core feature xmlBlaster offers you the ability to query for messages. This is great but what if you want to query xmlBlaster about other things ? The admin interface allows you to query things like sessionIds for a particular client, jvm used, uptime of the server and more.
To keep the querying capability open, a plugin approach for query specification has been designed. The interface to be implented by such plugins is org.xmlBlaster.engine.query.I_Query. The syntax of the query and the content of the returned Message Units is defined by a contract between the designer of the specific plugin and the client using it. This is pretty much the same as happens in the mime accessfilter plugin. As in the case of the later, the data to be used by the plugin is passed in the GetQos or in the SubscribeQos as an extra field called querySpec.


These is an example key and QoS of a subscribe() invocation:

   <key oid='__cmd:client/joe/session/1/?callbackQueueEntries' queryType='EXACT'>

      <querySpec type='QueueQuery' version='1.0'>

NOTE: Configuration parameters are specified on command line (-someValue 17) or in the xmlBlaster.properties file (someValue=17). See requirement "util.property" for details.
Columns named Impl tells you if the feature is implemented.
Columns named Hot tells you if the configuration is changeable in hot operation.

See API org.xmlBlaster.engine.query.I_Query
See API org.xmlBlaster.engine.query.plugins.QueueQueryPlugin
See API org.xmlBlaster.util.plugin.I_Plugin
See REQ mime.plugin.accessfilter
See REQ admin
See REQ admin.commands
See REQ admin.messages
See REQ engine.qos.queryspec.QueueQuery

This page is generated from the requirement XML file xmlBlaster/doc/requirements/engine.qos.queryspec.xml

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