/**
* Returns a collection of multiset entries representing the counts of the distinct elements, in
* sorted order. Does not check for null.
*/
public static <E> Collection<Multiset.Entry<E>> sortedCounts(
Comparator<? super E> comparator, Iterable<E> elements) {
if (elements instanceof Multiset) {
Multiset<E> multiset = (Multiset<E>) elements;
if (hasSameComparator(comparator, elements)) {
return multiset.entrySet();
}
List<Multiset.Entry<E>> entries = Lists.newArrayList(multiset.entrySet());
Collections.sort(
entries,
Ordering.from(comparator)
.onResultOf(
new Function<Multiset.Entry<E>, E>() {
@Override
public E apply(Entry<E> entry) {
return entry.getElement();
}
}));
return entries;
} else if (elements instanceof Set) { // known distinct
Collection<E> sortedElements;
if (hasSameComparator(comparator, elements)) {
sortedElements = (Collection<E>) elements;
} else {
List<E> list = Lists.newArrayList(elements);
Collections.sort(list, comparator);
sortedElements = list;
}
return singletonEntries(sortedElements);
} else if (hasSameComparator(comparator, elements)) {
E current = null;
int currentCount = 0;
List<Multiset.Entry<E>> sortedEntries = Lists.newArrayList();
for (E e : elements) {
if (currentCount > 0) {
if (comparator.compare(current, e) == 0) {
currentCount++;
} else {
sortedEntries.add(Multisets.immutableEntry(current, currentCount));
current = e;
currentCount = 1;
}
} else {
current = e;
currentCount = 1;
}
}
if (currentCount > 0) {
sortedEntries.add(Multisets.immutableEntry(current, currentCount));
}
return sortedEntries;
}
TreeMultiset<E> multiset = TreeMultiset.create(comparator);
Iterables.addAll(multiset, elements);
return multiset.entrySet();
}
/**
* Returns an immutable sorted multiset containing the given elements sorted by the given {@code
* Comparator}. This method iterates over {@code elements} at most once.
*
* <p>Despite the method name, this method attempts to avoid actually copying the data when it is
* safe to do so. The exact circumstances under which a copy will or will not be performed are
* undocumented and subject to change.
*
* @throws NullPointerException if {@code comparator} or any of {@code elements} is null
*/
public static <E> ImmutableSortedMultiset<E> copyOf(
Comparator<? super E> comparator, Iterable<? extends E> elements) {
if (elements instanceof ImmutableSortedMultiset) {
@SuppressWarnings("unchecked") // immutable collections are always safe for covariant casts
ImmutableSortedMultiset<E> multiset = (ImmutableSortedMultiset<E>) elements;
if (comparator.equals(multiset.comparator())) {
if (multiset.isPartialView()) {
return copyOfSortedEntries(comparator, multiset.entrySet().asList());
} else {
return multiset;
}
}
}
elements = Lists.newArrayList(elements); // defensive copy
TreeMultiset<E> sortedCopy = TreeMultiset.create(checkNotNull(comparator));
Iterables.addAll(sortedCopy, elements);
return copyOfSortedEntries(comparator, sortedCopy.entrySet());
}
/**
* Returns a collection of multiset entries representing the counts of the distinct elements, in
* sorted order. Does not check for null.
*/
public static <E> Collection<Multiset.Entry<E>> sortedCounts(
Comparator<? super E> comparator, Iterator<E> elements) {
TreeMultiset<E> multiset = TreeMultiset.create(comparator);
Iterators.addAll(multiset, elements);
return multiset.entrySet();
}