@Override
  public boolean contains(@CheckForNull Object element) {
    return count(element) > 0;
  }

  // Modification Operations
  @CanIgnoreReturnValue
  @Override
  public final boolean add(@ParametricNullness E element) {
    add(element, 1);
    return true;
  }

  @CanIgnoreReturnValue
  @Override
  public int add(@ParametricNullness E element, int occurrences) {
    throw new UnsupportedOperationException();

    MinMaxPriorityQueue<Element> queue = MinMaxPriorityQueue.create();
    int range = Element.values().length;
    for (int iter = 0; iter < reduceIterationsIfGwt(1000); iter++) {
      for (int i = 0; i < 100; i++) {
        Element element = Element.values()[random.nextInt(range)];
        elements.add(element);
        queue.add(element);
      }

 */
public class Indexed<T> {

    /** 要素 */
    private final T element;

    /** 要素のインデックス */
    private final int index;

    /**
     * コンストラクタ
     *
     * @param element
     *            要素
     * @param index
     *            要素のインデックス
     */
    public Indexed(final T element, final int index) {
        this.element = element;
        this.index = index;
    }

    /**
     * 要素を返します。

	default:
		return "unknown"
	}
}

// AccElem holds information for calculating an average value
type AccElem struct {
	Total int64
	Size  int64
	N     int64
}

// Add a duration to a single element.
func (a *AccElem) add(dur time.Duration) {
	if dur < 0 {
		dur = 0
	}
	a.Total += int64(dur)
	a.N++
}

// Merge b into a.
func (a *AccElem) merge(b AccElem) {
	a.N += b.N
	a.Total += b.Total

import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class MethodTableRenderer {
    public void renderTo(Iterable<MethodDoc> methods, Element parent) {
        Document document = parent.getOwnerDocument();

        // <thead>
        //   <tr>
        //     <td>Method</td>
        //     <td>Description</td>
        //   </tr>
        // </thead>
        Element thead = document.createElement("thead");

    }

    @Override
    public void renderSummaryTo(ClassDoc classDoc, Element parent) {
        Document document = parent.getOwnerDocument();

        Element summarySection = document.createElement("section");
        parent.appendChild(summarySection);

        Element title = document.createElement("title");
        summarySection.appendChild(title);

    }

    @Override
    public void renderSummaryTo(ClassDoc classDoc, Element parent) {
        Document document = parent.getOwnerDocument();

        Element summarySection = document.createElement("section");
        parent.appendChild(summarySection);

        Element title = document.createElement("title");
        summarySection.appendChild(title);

  public void testElement_empty() {
    assertThrows(NoSuchElementException.class, () -> getQueue().element());
    expectUnchanged();
  }

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

  @CollectionFeature.Require(KNOWN_ORDER)
  @CollectionSize.Require(SEVERAL)

    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

    }

    @Override
    public void renderSummaryTo(ClassDoc classDoc, Element parent) {
        Document document = parent.getOwnerDocument();

        Element summarySection = document.createElement("section");
        parent.appendChild(summarySection);

        Element title = document.createElement("title");
        summarySection.appendChild(title);