* Visit genclass index. Indexes can be find for List or Map implementation.
* @param sf a persistent field.
*/
private void visitGenClassIndex(SpeedoField sf) throws SpeedoException {
if (sf.jdoTuple instanceof SpeedoCollection) {
SpeedoCollection collec = (SpeedoCollection) sf.jdoTuple;
if (collec.indexColumns == null
&& List.class.isAssignableFrom(getGCClass(sf))) {
collec.indexColumns = new SpeedoColumn("idx", sf.join.extTable);
if (logger.isLoggable(BasicLevel.DEBUG)) {
logger.log(BasicLevel.DEBUG,