externalRequestSubsetter
Checks on the properties of a given request.
The jython class defined in class must implement Request like this example implementation.
For more information on externals, see the externals documentation
Example
<externalRequest>
    <classname>edu.somewhere.seis.sodExt.subsetter.request.MyRequest</classname>
</externalRequest>
    Places this can be found
In request there is a choice between all of the following