@Test
public void whenInsertDuplicatesInMultiSet_thenInserted() {
final Multiset<String> names = HashMultiset.create();
names.add("John");
names.add("Adam", 3);
names.add("John");
assertEquals(2, names.count("John"));
names.remove("John");
assertEquals(1, names.count("John"));
assertEquals(3, names.count("Adam"));
names.remove("Adam", 2);
assertEquals(1, names.count("Adam"));
}
@Override
public int remove(Object element, int occurrences) {
checkNonnegative(occurrences, "occurrences");
if (occurrences == 0) {
return count(element);
} else {
return contains(element) ? unfiltered.remove(element, occurrences) : 0;
}
}
@Override
public void remove() {
checkRemove(canRemove);
if (totalCount == 1) {
entryIterator.remove();
} else {
multiset.remove(currentEntry.getElement());
}
totalCount--;
canRemove = false;
}
/** An implementation of {@link Multiset#setCount(Object, int)}. */
static <E> int setCountImpl(Multiset<E> self, E element, int count) {
checkNonnegative(count, "count");
int oldCount = self.count(element);
int delta = count - oldCount;
if (delta > 0) {
self.add(element, delta);
} else if (delta < 0) {
self.remove(element, -delta);
}
return oldCount;
}
/**
* For each occurrence of an element {@code e} in {@code occurrencesToRemove}, removes one
* occurrence of {@code e} in {@code multisetToModify}.
*
* <p>Equivalently, this method modifies {@code multisetToModify} so that {@code
* multisetToModify.count(e)} is set to {@code Math.max(0, multisetToModify.count(e) -
* Iterables.frequency(occurrencesToRemove, e))}.
*
* <p>This is <i>not</i> the same as {@code multisetToModify.} {@link Multiset#removeAll
* removeAll}{@code (occurrencesToRemove)}, which removes all occurrences of elements that appear
* in {@code occurrencesToRemove}. However, this operation <i>is</i> equivalent to, albeit
* sometimes more efficient than, the following:
*
* <pre>{@code
* for (E e : occurrencesToRemove) {
* multisetToModify.remove(e);
* }
* }</pre>
*
* @return {@code true} if {@code multisetToModify} was changed as a result of this operation
* @since 18.0 (present in 10.0 with a requirement that the second parameter be a {@code
* Multiset})
*/
public static boolean removeOccurrences(
Multiset<?> multisetToModify, Iterable<?> occurrencesToRemove) {
if (occurrencesToRemove instanceof Multiset) {
return removeOccurrences(multisetToModify, (Multiset<?>) occurrencesToRemove);
} else {
checkNotNull(multisetToModify);
checkNotNull(occurrencesToRemove);
boolean changed = false;
for (Object o : occurrencesToRemove) {
changed |= multisetToModify.remove(o);
}
return changed;
}
}
/**
* For each occurrence of an element {@code e} in {@code occurrencesToRemove}, removes one
* occurrence of {@code e} in {@code multisetToModify}.
*
* <p>Equivalently, this method modifies {@code multisetToModify} so that {@code
* multisetToModify.count(e)} is set to {@code Math.max(0, multisetToModify.count(e) -
* occurrencesToRemove.count(e))}.
*
* <p>This is <i>not</i> the same as {@code multisetToModify.} {@link Multiset#removeAll
* removeAll}{@code (occurrencesToRemove)}, which removes all occurrences of elements that appear
* in {@code occurrencesToRemove}. However, this operation <i>is</i> equivalent to, albeit
* sometimes more efficient than, the following:
*
* <pre>{@code
* for (E e : occurrencesToRemove) {
* multisetToModify.remove(e);
* }
* }</pre>
*
* @return {@code true} if {@code multisetToModify} was changed as a result of this operation
* @since 10.0 (missing in 18.0 when only the overload taking an {@code Iterable} was present)
*/
public static boolean removeOccurrences(
Multiset<?> multisetToModify, Multiset<?> occurrencesToRemove) {
checkNotNull(multisetToModify);
checkNotNull(occurrencesToRemove);
boolean changed = false;
Iterator<? extends Entry<?>> entryIterator = multisetToModify.entrySet().iterator();
while (entryIterator.hasNext()) {
Entry<?> entry = entryIterator.next();
int removeCount = occurrencesToRemove.count(entry.getElement());
if (removeCount >= entry.getCount()) {
entryIterator.remove();
changed = true;
} else if (removeCount > 0) {
multisetToModify.remove(entry.getElement(), removeCount);
changed = true;
}
}
return changed;
}
