How to use

setCount

method

in

com.google.common.collect.Multiset

@Override
public boolean setCount(E element, int oldCount, int newCount) {
 synchronized (mutex) {
  return delegate().setCount(element, oldCount, newCount);
 }
}

@Override
public int setCount(E element, int count) {
 synchronized (mutex) {
  return delegate().setCount(element, count);
 }
}

 private int setCount(E element, int count) {
  return getMultiset().setCount(element, count);
 }
}

/**
 * Adds or removes the necessary occurrences of an element such that the element attains the
 * desired count.
 *
 * @param element the element to add or remove occurrences of
 * @param count the desired count of the element in this multiset
 * @return this {@code Builder} object
 * @throws NullPointerException if {@code element} is null
 * @throws IllegalArgumentException if {@code count} is negative
 */
@CanIgnoreReturnValue
public Builder<E> setCount(E element, int count) {
 contents.setCount(checkNotNull(element), count);
 return this;
}

@CanIgnoreReturnValue
@Override
public int setCount(E element, int count) {
 return delegate().setCount(element, count);
}

@CanIgnoreReturnValue
@Override
public boolean setCount(E element, int oldCount, int newCount) {
 return delegate().setCount(element, oldCount, newCount);
}

@Override
public int setCount(E element, int count) {
 synchronized (mutex) {
  return delegate().setCount(element, count);
 }
}

/** Delegate implementation which cares about the element type. */
private static <E> boolean retainOccurrencesImpl(
  Multiset<E> multisetToModify, Multiset<?> occurrencesToRetain) {
 checkNotNull(multisetToModify);
 checkNotNull(occurrencesToRetain);
 // Avoiding ConcurrentModificationExceptions is tricky.
 Iterator<Entry<E>> entryIterator = multisetToModify.entrySet().iterator();
 boolean changed = false;
 while (entryIterator.hasNext()) {
  Entry<E> entry = entryIterator.next();
  int retainCount = occurrencesToRetain.count(entry.getElement());
  if (retainCount == 0) {
   entryIterator.remove();
   changed = true;
  } else if (retainCount < entry.getCount()) {
   multisetToModify.setCount(entry.getElement(), retainCount);
   changed = true;
  }
 }
 return changed;
}

private void assertSetCountNegativeOldCount() {
 try {
  getMultiset().setCount(e3(), -1, 1);
  fail("calling setCount() with a negative oldCount should throw IllegalArgumentException");
 } catch (IllegalArgumentException expected) {
 }
}

/** An implementation of {@link Multiset#setCount(Object, int, int)}. */
static <E> boolean setCountImpl(Multiset<E> self, E element, int oldCount, int newCount) {
 checkNonnegative(oldCount, "oldCount");
 checkNonnegative(newCount, "newCount");
 if (self.count(element) == oldCount) {
  self.setCount(element, newCount);
  return true;
 } else {
  return false;
 }
}

@CanIgnoreReturnValue
@Override
public boolean setCount(E element, int oldCount, int newCount) {
 return delegate().setCount(element, oldCount, newCount);
}

@CanIgnoreReturnValue
@Override
public int setCount(E element, int count) {
 return delegate().setCount(element, count);
}

private boolean setCount(E element, int count) {
 return getMultiset().setCount(element, getMultiset().count(element), count);
}

@SuppressWarnings("cast")
@Override
public boolean remove(Object object) {
 if (object instanceof Multiset.Entry) {
  Entry<?> entry = (Entry<?>) object;
  Object element = entry.getElement();
  int entryCount = entry.getCount();
  if (entryCount != 0) {
   // Safe as long as we never add a new entry, which we won't.
   @SuppressWarnings("unchecked")
   Multiset<Object> multiset = (Multiset) multiset();
   return multiset.setCount(element, entryCount, 0);
  }
 }
 return false;
}

@CanIgnoreReturnValue
@Override
public int setCount(E element, int count) {
 return delegate().setCount(element, count);
}

@CanIgnoreReturnValue
@Override
public boolean setCount(E element, int oldCount, int newCount) {
 return delegate().setCount(element, oldCount, newCount);
}

@CollectionFeature.Require(SUPPORTS_ADD)
public void testSetCountConditional_oldCountTooLarge() {
 assertFalse(
   "setCount() with a too-large oldCount should return false",
   getMultiset().setCount(e0(), 2, 3));
 expectUnchanged();
}

@SuppressWarnings("cast")
@Override
public boolean remove(Object object) {
 if (object instanceof Multiset.Entry) {
  Entry<?> entry = (Entry<?>) object;
  Object element = entry.getElement();
  int entryCount = entry.getCount();
  if (entryCount != 0) {
   // Safe as long as we never add a new entry, which we won't.
   @SuppressWarnings("unchecked")
   Multiset<Object> multiset = (Multiset) multiset();
   return multiset.setCount(element, entryCount, 0);
  }
 }
 return false;
}

@CollectionSize.Require(SEVERAL)
@CollectionFeature.Require(SUPPORTS_ADD)
public void testSetCountConditional_oldCountTooSmallNonzero() {
 initThreeCopies();
 assertFalse(
   "setCount() with a too-small oldCount should return false",
   getMultiset().setCount(e0(), 1, 5));
 expectContents(nCopies(3, e0()));
}

@CollectionSize.Require(absent = ZERO)
@CollectionFeature.Require(SUPPORTS_ADD)
public void testSetCountConditional_oldCountTooSmallZero() {
 assertFalse(
   "setCount() with a too-small oldCount should return false",
   getMultiset().setCount(e0(), 0, 2));
 expectUnchanged();
}