/**
* Overlays this fragment list by some {@link Fragment}. That means that parts that overlap are
* taken from the fragment passed.
*
* @param fragment The fragment.
* @return A fragment list storing the overlay result.
*/
public FragmentList overlayBy(final Fragment fragment) {
final FragmentList result = new FragmentList();
try {
result.addFragment(fragment);
} catch (final IncompatibleFragmentException e) {
throw new Error(e);
}
final PositionInText posTo = fragment.getTo();
final ListIterator<Fragment> it = this.fragments.listIterator();
while (it.hasNext()) {
final Fragment oldFragment = it.next();
if (posTo.lessThan(oldFragment.getFrom())) {
break;
}
final ListIterator<Fragment> fIt = result.fragments.listIterator();
while (fIt.hasNext()) {
final Fragment f = fIt.next();
final FragmentList rest = f.subtract(oldFragment);
fIt.remove();
for (final Fragment newFragment : rest.fragments) {
fIt.add(newFragment);
}
}
}
try {
result.addFragmentList(this);
} catch (final IncompatibleFragmentException e) {
throw new Error(e);
}
return result;
}
/**
* Subtracts some {@link Fragment} from this fragment list.
*
* @param fragment The fragment to subtract.
* @return A list of remaining fragments.
*/
public FragmentList subtract(final Fragment fragment) {
final FragmentList result = new FragmentList();
try {
for (final Fragment oldFragment : this.fragments) {
if (oldFragment.overlaps(fragment)) {
result.addFragmentList(oldFragment.subtract(fragment));
} else {
result.addFragment(oldFragment);
}
}
} catch (final IncompatibleFragmentException e) {
throw new Error(e);
}
return result;
}