* #add(Object, int) add}{@code (element, 1)} instead.
   *
   * @param element the element to add one occurrence of; may be null only if explicitly allowed by
   *     the implementation
   * @return {@code true} always, since this call is required to modify the multiset, unlike other
   *     {@link Collection} types

  // 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(@CheckForNull Object element) {
    AtomicInteger existingCounter = Maps.safeGet(countMap, element);
    return (existingCounter == null) ? 0 : existingCounter.get();
  }

   * Creates a new {@code EnumMultiset} containing the specified elements.
   *
   * <p>This implementation is highly efficient when {@code elements} is itself a {@link Multiset}.
   *
   * @param elements the elements that the multiset should contain
   * @throws IllegalArgumentException if {@code elements} is empty
   */
  public static <E extends Enum<E>> EnumMultiset<E> create(Iterable<E> elements) {
    Iterator<E> iterator = elements.iterator();

      for (Object o : extras) {
        sb.append(", ").append(o);
      }
      if (overflow) {
        sb.append(", ...");
      }
      sb.append('>');
      throw new IllegalArgumentException(sb.toString());
    }

    void add(Object o) {
      checkNotNull(o);
      if (element == null) {
        this.element = o;

      Iterable<? extends @Nullable Object> iterable, @CheckForNull Object element) {
    if (iterable instanceof Collection) {
      Collection<?> collection = (Collection<?>) iterable;
      return Collections2.safeContains(collection, element);
    }
    return Iterators.contains(iterable.iterator(), element);
  }

  /**
   * Removes, from an iterable, every element that belongs to the provided collection.
   *

      return standardAddAll(collection);
    }

    @Override
    public boolean add(T element) {
      return standardAdd(element);
    }

    @Override
    public void clear() {
      standardClear();
    }

    @Override
    public int count(Object element) {
      return standardCount(element);
    }

    @Override
    public boolean contains(Object object) {

   * @since 3.0
   */
  public static <E> ImmutableList<E> copyOf(E[] elements) {
    switch (elements.length) {
      case 0:
        return of();
      case 1:
        return of(elements[0]);
      default:
        return construct(elements.clone());
    }
  }

  /**

import java.util.NoSuchElementException;
import javax.annotation.CheckForNull;

/**
 * This class provides a skeletal implementation of the {@code Iterator} interface for sequences
 * whose next element can always be derived from the previous element. Null elements are not
 * supported, nor is the {@link #remove()} method.
 *
 * <p>Example:
 *
 * <pre>{@code
 * Iterator<Integer> powersOfTwo =
 *     new AbstractSequentialIterator<Integer>(1) {

    }

    /**
     * {@link Element}を文字列に変換します。
     *
     * @param element
     *            要素。{@literal null}であってはいけません
     * @return 変換された文字列
     */
    public static String toString(final Element element) {
        assertArgumentNotNull("element", element);

        final StringBuilder buf = new StringBuilder(1000);
        appendElement(element, buf);
        return new String(buf);
    }

  public void testElement_empty() {
    try {
      getQueue().element();
      fail("emptyQueue.element() should throw");
    } catch (NoSuchElementException expected) {
    }
    expectUnchanged();
  }

  @CollectionSize.Require(ONE)
  public void testElement_size1() {
    assertEquals("size1Queue.element() should return first element", e0(), getQueue().element());
    expectUnchanged();
  }