This Validator is able to scan all fields defined in the current Screen (Create, Edit or Workflow Transition).
And it evaluate the respect of Regular Expression for Field based RegExpCFType.
n/c
The Validator configuration may be done in XML in Workflow descriptor as follow :
<validators> <validator name="" type="class"> <arg name="class.name">com.atlassian.jira.workflow.validator.RegExpCustomFieldValidator</arg> </validator> </validators>