code: private void addClass(ClassDoc classdoc, Map<String,Set<ClassDoc>> map) {
  
            PackageDoc pkg = classdoc.containingPackage();
            if (pkg.isIncluded() || (configuration.nodeprecated && Util.isDeprecated(pkg))) {
                //No need to catalog this class if it's package is
                //included on the command line or if -nodeprecated option is set
                // and the containing package is marked as deprecated.
                return;
            }
            String key = Util.getPackageName(pkg);
            Set<ClassDoc> s = map.get(key);
            if (s == null) {
                packageSet.add(key);
                s = new HashSet<ClassDoc>();
            }
            s.add(classdoc);
            map.put(key, s);
  
        }
docs: Add the given class to the given map.
  @param classdoc the ClassDoc to add to the catelog.
  @param map the Map to add the ClassDoc to.