/**
  * Gets a {@link mondrian.rolap.aggmatcher.Recognizer.Matcher} for a given level's hierarchy's
  * name, level name and column name.
  */
 public Recognizer.Matcher getLevelMatcher(
     final String usagePrefix,
     final String hierarchyName,
     final String levelName,
     final String levelColumnName) {
   DefaultDef.AggRule rule = getAggRule();
   Recognizer.Matcher matcher =
       rule.getLevelMap().getMatcher(usagePrefix, hierarchyName, levelName, levelColumnName);
   return matcher;
 }