registers a listener that is notified of each comparison . concode_field_sep List<ComparisonListener> matchListeners concode_elem_sep List<ComparisonListener> compListeners concode_elem_sep List<ComparisonListener> diffListeners concode_field_sep void addDifferenceListener concode_elem_sep void addMatchListener concode_elem_sep void fire concode_elem_sep void fireComparisonPerformed