Request selectors are referenced by the TestSet of a SubprocessPool to determine if an Arbortext PE sub-process pool should service a request. They can be grouped by And and Or elements within a TestSet to set up more complex acceptance criteria.

Individual Request Selectors are invoked when a Arbortext PE sub-process pool evaluates a call to its testRequest method to determine whether its Arbortext PE sub-processes should be allocated to a particular HTTP request. testRequest is normally called by the Arbortext Publishing Engine Request Context as part of evaluating its allocateE3Subprocess method.