nl.vpro.util.SortedSetElementWrapper Maven / Gradle / Ivy
package nl.vpro.util;
import java.util.AbstractSet;
import java.util.Comparator;
import java.util.Iterator;
import java.util.SortedSet;
import org.checkerframework.checker.nullness.qual.NonNull;
/**
* @author Michiel Meeuwissen
* @since 2.3.1
*/
public abstract class SortedSetElementWrapper extends AbstractSet implements SortedSet {
protected final SortedSet wrapped;
public SortedSetElementWrapper(SortedSet wrapped) {
if (wrapped == null) {
throw new IllegalArgumentException("Cannot wrap null");
}
this.wrapped = wrapped;
}
@NonNull
@Override
public Iterator iterator() {
return new Iterator() {
final Iterator iterator = wrapped.iterator();
@Override
public boolean hasNext() {
return iterator.hasNext();
}
@Override
public S next() {
return adapt(iterator.next());
}
@Override
public void remove() {
iterator.remove();
}
};
}
@Override
public int size() {
return wrapped.size();
}
@Override
public Comparator comparator() {
return (Comparator) (o1, o2) -> wrapped.comparator().compare(find(o1), find(o2));
}
@NonNull
@Override
public SortedSet subSet(S fromElement, S toElement) {
return sub(wrapped.subSet(find(fromElement), find(toElement)));
}
@NonNull
@Override
public SortedSet headSet(S toElement) {
return sub(wrapped.headSet(find(toElement)));
}
@NonNull
@Override
public SortedSet tailSet(S fromElement) {
return sub(wrapped.tailSet(find(fromElement)));
}
@Override
public S first() {
return adapt(wrapped.first());
}
@Override
public S last() {
return adapt(wrapped.last());
}
protected SortedSet sub(SortedSet wrapped) {
return new SortedSetElementWrapper(wrapped) {
@Override
protected S adapt(T element) {
return SortedSetElementWrapper.this.adapt(element);
}
};
}
protected T find(S element) {
for (T t : wrapped) {
if (adapt(t).equals(element)) {
return t;
}
}
return null;
}
protected abstract S adapt(T element);
}