final TreeSet<SpaceInformation> spaceInformations = new TreeSet<SpaceInformation>( getSpaceInformations()); YearMonthDay previousValidUntil = getCreatedOn(); for (final SpaceInformation spaceInformation : spaceInformations) { spaceInformation.setValidFrom(previousValidUntil); previousValidUntil = spaceInformation.getValidUntil(); } return spaceInformations;
return new TreeSet<SpaceInformation>(getSpaceInformations());
    public SortedSet<SpaceInformation> getOrderedSpaceInformations() {	final TreeSet<SpaceInformation> spaceInformations = new TreeSet<SpaceInformation>(		getSpaceInformations());	YearMonthDay previousValidUntil = getCreatedOn();	for (final SpaceInformation spaceInformation : spaceInformations) {	    spaceInformation.setValidFrom(previousValidUntil);	    previousValidUntil = spaceInformation.getValidUntil();	}	return spaceInformations;    }