checkNonnegative(oldCount, "oldCount");
    checkNonnegative(newCount, "newCount");
    int entryIndex = backingMap.indexOf(element);
    if (entryIndex == -1) {
      if (oldCount != 0) {
        return false;
      }
      if (newCount > 0) {
        backingMap.put(element, newCount);
        size += newCount;
      }
      return true;
    }

    AtomicInteger existingCounter = safeGet(countMap, element);
    if (existingCounter == null) {
      if (expectedOldCount != 0) {
        return false;
      } else if (newCount == 0) {
        return true;
      } else {
        // if our write lost the race, it must have lost to a nonzero value, so we can stop
        return countMap.putIfAbsent(element, new AtomicInteger(newCount)) == null;

  public boolean setCount(@ParametricNullness E element, int oldCount, int newCount) {
    checkNonnegative(newCount, "newCount");
    checkNonnegative(oldCount, "oldCount");
    checkArgument(range.contains(element));

    AvlNode<E> root = rootReference.get();
    if (root == null) {
      if (oldCount == 0) {
        if (newCount > 0) {
          add(element, newCount);
        }
        return true;
      } else {

    AtomicInteger existingCounter = safeGet(countMap, element);
    if (existingCounter == null) {
      if (expectedOldCount != 0) {
        return false;
      } else if (newCount == 0) {
        return true;
      } else {
        // if our write lost the race, it must have lost to a nonzero value, so we can stop
        return countMap.putIfAbsent(element, new AtomicInteger(newCount)) == null;

     *     method will return {@code true} if the condition was met.
     * @throws IllegalArgumentException if {@code oldCount} or {@code newCount} is negative
     */
    @Override
    public boolean setCount(E element, int oldCount, int newCount) {
      checkNonnegative(oldCount, "oldCount");
      checkNonnegative(newCount, "newCount");
      if (newCount == 0) {

      return count(element);
    }
    int index = element.ordinal();
    int oldCount = counts[index];
    long newCount = (long) oldCount + occurrences;
    checkArgument(newCount <= Integer.MAX_VALUE, "too many occurrences: %s", newCount);
    counts[index] = (int) newCount;
    if (oldCount == 0) {
      distinctElements++;
    }
    size += occurrences;
    return oldCount;
  }

      lock();
      try {
        long now = map.ticker.read();
        preWriteCleanup(now);

        int newCount = this.count + 1;
        if (newCount > this.threshold) { // ensure capacity
          expand();
          newCount = this.count + 1;
        }

        AtomicReferenceArray<ReferenceEntry<K, V>> table = this.table;
        int index = hash & (table.length() - 1);

    @Nullable V put(K key, int hash, V value, boolean onlyIfAbsent) {
      lock();
      try {
        preWriteCleanup();

        int newCount = this.count + 1;
        if (newCount > this.threshold) { // ensure capacity
          expand();
          newCount = this.count + 1;
        }

        AtomicReferenceArray<E> table = this.table;
        int index = hash & (table.length() - 1);

      return count(element);
    }
    int index = element.ordinal();
    int oldCount = counts[index];
    long newCount = (long) oldCount + occurrences;
    checkArgument(newCount <= Integer.MAX_VALUE, "too many occurrences: %s", newCount);
    counts[index] = (int) newCount;
    if (oldCount == 0) {
      distinctElements++;
    }
    size += occurrences;
    return oldCount;
  }

    @Nullable V put(K key, int hash, V value, boolean onlyIfAbsent) {
      lock();
      try {
        preWriteCleanup();

        int newCount = this.count + 1;
        if (newCount > this.threshold) { // ensure capacity
          expand();
          newCount = this.count + 1;
        }

        AtomicReferenceArray<E> table = this.table;
        int index = hash & (table.length() - 1);