* Combine all VisitListener filters in one logical filter to rule out artifacts that are not needed by any listener.
*
* @return the filter that rejects all artifacts that are analyzed by no listener
*/
private Filter createPrefilter() {
LogicalOrFilter filter = new LogicalOrFilter();
for (VisitListener visitListener : visitorList) {
Filter subfilter = visitListener.getVisitFilter();
if (subfilter == null) {
return new ConstantFilter(true);
}
filter.addFilter(subfilter);
}
return filter;
}