}
IConfigurationElement[] placements= element.getChildren(PLACEMENT);
switch (placements.length) {
case 0:
fRulerColumnPlacement= new RulerColumnPlacement();
break;
case 1:
fRulerColumnPlacement= new RulerColumnPlacement(placements[0]);
break;
default:
helper.fail(RulerColumnMessages.RulerColumnDescriptor_invalid_placement_msg);
fRulerColumnPlacement= null; // dummy
break;