/** Clear all properties that already exist in destination PropertySet. */
  private void clearDestination() throws PropertyException {
    Iterator keys = destination.getKeys().iterator();

    while (keys.hasNext()) {
      String key = (String) keys.next();
      destination.remove(key);
    }
  }
  public void cloneProperties() throws PropertyException {
    clearDestination();

    Iterator keys = source.getKeys().iterator();

    while (keys.hasNext()) {
      String key = (String) keys.next();
      cloneProperty(key);
    }
  }