// Query Operations

  /**
   * Returns the number of occurrences of {@code element} in this multiset.
   *
   * @param element the element to look for
   * @return the nonnegative number of occurrences of the element
   */
  @Override
  public int count(@Nullable Object element) {
    AtomicInteger existingCounter = safeGet(countMap, element);
    return (existingCounter == null) ? 0 : existingCounter.get();
  }

    if (occurrences == 0) {
      return count(element);
    }
    checkArgument(occurrences > 0, "occurrences cannot be negative: %s", occurrences);
    int entryIndex = backingMap.indexOf(element);
    if (entryIndex == -1) {
      backingMap.put(element, occurrences);
      size += occurrences;
      return 0;
    }
    int oldCount = backingMap.getValue(entryIndex);

 * according to when the first occurrence of the element was added. When the multiset contains
 * multiple instances of an element, those instances are consecutive in the iteration order. If all
 * occurrences of an element are removed, after which that element is added to the multiset, the
 * element will appear at the end of the iteration.
 *
 * <p>See the Guava User Guide article on <a href=

    T[] result = newArray(array, array.length + 1);
    result[0] = element;
    arraycopy(array, 0, result, 1, array.length);
    return result;
  }

  /**
   * Returns a new array that appends {@code element} to {@code array}.
   *
   * @param array the array of elements to prepend
   * @param element the element to append to the end

    T[] result = newArray(array, array.length + 1);
    result[0] = element;
    arraycopy(array, 0, result, 1, array.length);
    return result;
  }

  /**
   * Returns a new array that appends {@code element} to {@code array}.
   *
   * @param array the array of elements to prepend
   * @param element the element to append to the end

    public static final String CONTAINS = "contains:";

    /** XML element name for collections container. */
    protected static final String COLLECTIONS = "collections";

    /** XML element name for individual collection. */
    protected static final String COLLECTION = "collection";

    /** XML element name for global parameters container. */
    protected static final String GLOBALPARAMS = "globalparams";

  @Override
  public int add(@ParametricNullness E element, int occurrences) {
    checkNonnegative(occurrences, "occurrences");
    if (occurrences == 0) {
      return count(element);
    }
    checkArgument(range.contains(element));
    AvlNode<E> root = rootReference.get();
    if (root == null) {
      int unused = comparator().compare(element, element);
      AvlNode<E> newRoot = new AvlNode<>(element, occurrences);

  @Override
  public int add(@ParametricNullness E element, int occurrences) {
    checkNonnegative(occurrences, "occurrences");
    if (occurrences == 0) {
      return count(element);
    }
    checkArgument(range.contains(element));
    AvlNode<E> root = rootReference.get();
    if (root == null) {
      int unused = comparator().compare(element, element);
      AvlNode<E> newRoot = new AvlNode<>(element, occurrences);

   * support concurrent multisets whose content may change while the method is running.
   *
   * <p>The serialized output consists of the number of distinct elements, the first element, its
   * count, the second element, its count, and so on.
   */
  static <E extends @Nullable Object> void writeMultiset(
      Multiset<E> multiset, ObjectOutputStream stream) throws IOException {

    /**
     * This default mode for combining a DOM node during merge means that where element names match, the process will
     * try to merge the element attributes and values, rather than overriding the recessive element completely with the
     * dominant one. This means that wherever the dominant element doesn't provide the value or a particular attribute,
     * that value or attribute will be set from the recessive DOM node.