public String saveRequirements() {
PrepareChangesForPersist prep = new PrepareChangesForPersist(user.getUsername());
// before persisting: adjust all scales of leaves
List<Leaf> leaves = reqexpTree.getRoot().getAllLeaves();
MeasurementsDescriptor descriptor = MiniRED.getInstance().getMeasurementsDescriptor();
for (Leaf l : leaves) {
MeasurementInfoUri mInfo = l.getMeasurementInfo().toMeasurementInfoUri();
if (mInfo.getAsURI() != null) {
Scale s = descriptor.getMeasurementScale(mInfo);
if (s != null) {
l.adjustScale(s);
}
}
}