/* (non-Javadoc)
  * @see org.csstudio.archive.reader.ValueIterator#close()
  */
 @Override
 public void close() {
   try {
     synchronized (this) {
       if (stdStream != null) {
         stdStream.close();
       }
       if (minStream != null) {
         minStream.close();
       }
       if (maxStream != null) {
         maxStream.close();
       }
       if (countStream != null) {
         countStream.close();
       }
       super.close();
     }
   } catch (IOException e) {
     throw new IllegalStateException(e);
   }
 }