ui/src/main/java/thredds/ui/datatype/prefs/DurationField.java
protected void setEditValue(Object value) {
    if (value == null)
      tf.setText("");
    else
      tf.setText(value.toString());
    // tf.repaint();
  }
protected void setEditValue(Object value) {
    if (value == null)
      tf.setText("");
    else
      tf.setText(value.toString());
    // tf.repaint();
  }
set current value of editComponent