code: public boolean regenerateField(String name) throws IOException, DocumentException {
      	String value = getField(name);
          return setField(name, value, value);
      }
docs: Regenerates the field appearance.
  This is useful when you change a field property, but not its value,
  for instance form.setFieldProperty("f", "bgcolor", Color.BLUE, null);
  This won't have any effect, unless you use regenerateField("f") after changing
  the property.
  
  @param name the fully qualified field name or the partial name in the case of XFA forms
  @throws IOException on error
  @throws DocumentException on error
  @return <CODE>true</CODE> if the field was found and changed,
  <CODE>false</CODE> otherwise