1. Any significant changes should be accompanied by tests. The project already
     has good test coverage, so look at some existing tests if you're unsure
     how to go about it.
  2. All contributions must be licensed Apache 2.0 and all files must have a
     copy of the boilerplate license comment (can be copied from an existing
     file).
  3. Files should be formatted according to Google's [Java style guide][].

    assertWithTemplate(
        "$ITEM must be $RELATIONSHIP to $OTHER",
        itemInfo,
        relatedInfo,
        equivalence.equivalent(item, related));

    int itemHash = equivalence.hash(item);
    int relatedHash = equivalence.hash(related);
    assertWithTemplate(
        "the $HASH ("
            + itemHash
            + ") of $ITEM must be equal to the $HASH ("
            + relatedHash

 * is built into the language and runtime. But the programmer has to remember to avoid a couple of
 * common bugs: The {@code wait()} must be inside a {@code while} instead of an {@code if}, and
 * {@code notifyAll()} must be used instead of {@code notify()} because there are two different
 * logical conditions being awaited.
 *
 * <pre>{@code
 * public class SafeBox<V> {
 *   private V value;
 *

                format("key %s invalid unit: was %s, must end with one of [dhms]", key, value));
        }

        long duration = Long.parseLong(value.substring(0, value.length() - 1));
        parseDuration(spec, duration, timeUnit);
      } catch (NumberFormatException e) {
        throw new IllegalArgumentException(
            format("key %s value set to %s, must be integer", key, value));
      }
    }
  }

be able!  I shall be a great deal too far off to trouble myself
about you:  you must manage the best way you can; --but I must be
kind to them,' thought Alice, `or perhaps they won't walk the
way I want to go!  Let me see:  I'll give them a new pair of
boots every Christmas.'

  And she went on planning to herself how she would manage it.
`They must go by the carrier,' she thought; `and how funny it'll

public final class SpliteratorTester<E extends @Nullable Object> {
  /** Return type from "contains the following elements" assertions. */
  public interface Ordered {
    /**
     * Attests that the expected values must not just be present but must be present in the order
     * they were given.
     */
    void inOrder();
  }

  private abstract static class GeneralSpliterator<E extends @Nullable Object> {
    final Spliterator<E> spliterator;

    checkArgument(iterator.hasNext(), "Must be at least 1 hash code to combine.");
    int bits = iterator.next().bits();
    byte[] resultBytes = new byte[bits / 8];
    for (HashCode hashCode : hashCodes) {
      byte[] nextBytes = hashCode.asBytes();
      checkArgument(
          nextBytes.length == resultBytes.length, "All hashcodes must have the same bit length.");

  /**
   * Creates a new, empty multiset, sorted according to the elements' natural order. All elements
   * inserted into the multiset must implement the {@code Comparable} interface. Furthermore, all
   * such elements must be <i>mutually comparable</i>: {@code e1.compareTo(e2)} must not throw a
   * {@code ClassCastException} for any elements {@code e1} and {@code e2} in the multiset. If the

 * {@link #putString(CharSequence, Charset)} is generally only useful for cross-language
 * compatibility (otherwise prefer {@link #putUnencodedChars}). However, the character encodings
 * must be identical across languages. Also beware that {@link Charset} definitions may occasionally
 * change between Java releases.
 *
 * <p><b>Warning:</b> Chunks of data that are put into the {@link Hasher} are not delimited. The

public interface Weigher<K, V> {

  /**
   * Returns the weight of a cache entry. There is no unit for entry weights; rather they are simply
   * relative to each other.
   *
   * @return the weight of the entry; must be non-negative
   */
  int weigh(K key, V value);