docs: ContentMatcher nextMatcher(Conjunction selector, ContentMatcher oldMatcher) {
      if (tc.isEntryEnabled())
        tc.entry(this,cclass, "nextMatcher", "selector: "+selector+", oldMatcher: "+oldMatcher);
      ContentMatcher ans;
      if (!cacheing)
        ans = super.nextMatcher(selector, oldMatcher);
      else if (oldMatcher == null)
        ans = new CacheingMatcher(ordinalPosition, super.nextMatcher(selector, null));   
      else 
        ans = oldMatcher;
      if (tc.isEntryEnabled())
        tc.exit(this,cclass, "nextMatcher", ans);
      return ans;
    }