@Override
public NavigableSet<E> subSet(
E fromElement, boolean fromInclusive, E toElement, boolean toInclusive) {
synchronized (mutex) {
return Synchronized.navigableSet(
delegate().subSet(fromElement, fromInclusive, toElement, toInclusive), mutex);
}
}
@Override
public NavigableSet<K> navigableKeySet() {
synchronized (mutex) {
if (navigableKeySet == null) {
return navigableKeySet = Synchronized.navigableSet(delegate().navigableKeySet(), mutex);
}
return navigableKeySet;
}
}
@Override
public NavigableSet<K> descendingKeySet() {
synchronized (mutex) {
if (descendingKeySet == null) {
return descendingKeySet = Synchronized.navigableSet(delegate().descendingKeySet(), mutex);
}
return descendingKeySet;
}
}
@Override
public NavigableSet<E> descendingSet() {
synchronized (mutex) {
if (descendingSet == null) {
NavigableSet<E> dS = Synchronized.navigableSet(delegate().descendingSet(), mutex);
descendingSet = dS;
return dS;
}
return descendingSet;
}
}
@Override
public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
synchronized (mutex) {
return Synchronized.navigableSet(delegate().tailSet(fromElement, inclusive), mutex);
}
}
@Override
public NavigableSet<E> headSet(E toElement, boolean inclusive) {
synchronized (mutex) {
return Synchronized.navigableSet(delegate().headSet(toElement, inclusive), mutex);
}
}