Pre-Query Plugin
- Shaun Morris
Usage
Pre-Query plugins are invoked before a query operation is sent to any of the Sources. This is an opportunity to take any action on the query, including but not limited to:
- validation
- logging
- auditing
- optimization
- security filtering
Failure Behavior
In the event that this Catalog Plugin cannot operate but does not wish to fail the transaction, a PluginExecutionException will be thrown. For any other Exceptions, the Catalog will "fail safe" and the Operation will be cancelled. If processing is to be explicitly stopped, a StopProcessingException will be thrown.
Failure Behavior
In the event that this Catalog Plugin cannot operate but does not wish to fail the transaction, a PluginExecutionException will be thrown. For any other Exceptions, the Catalog will "fail safe" and the Operation will be cancelled. If processing is to be explicitly stopped, a StopProcessingException will be thrown.
Invocation
Pre-Query plugins are invoked serially, prioritized by descending OSGi service ranking. That is, the plugin with the highest service ranking will be executed first.
The output of a Pre-Query plugin is sent to the next Pre-Query plugin, until all have executed and the query operation is sent to the requested Source.