code: public String[] getAllGlobusID(String userID) {
          if (userID == null) {
              throw new IllegalArgumentException(i18n.getMessage("userIdNull"));
          }
  
          if (this.map == null) {
              return null;
          }
  
          Vector v = new Vector();
  
          Iterator iter = this.map.entrySet().iterator();
          Map.Entry mapEntry;
          GridMapEntry entry;
          while(iter.hasNext()) {
              mapEntry = (Map.Entry)iter.next();
              entry = (GridMapEntry)mapEntry.getValue();
              if (entry.containsUserID(userID)) {
                  v.add(entry.getGlobusID());
             }
          }
  
          // create array of strings and add values back in
          if(v.size() == 0) {
              return null;
          }
  
          String idS[] = new String[v.size()];
          for(int ctr = 0; ctr < v.size(); ctr++) {
              idS[ctr] = (String) v.elementAt(ctr);
          }
  
          return idS;
      }
docs: Returns all globus IDs associated with the
  specified local user name.
  
  @param userID local user name
  @return associated globus ID, null
  if there is not any.