// We assume that all defaults are generics-safe, even if they aren't,
    // we take the risk.
    @SuppressWarnings("unchecked")
    T defaultValue = (T) defaults.getInstance(type.getRawType());
    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // All arbitrary instances are generics-safe
    T arbitrary = (T) ArbitraryInstances.get(type.getRawType());

   * false} for {@code boolean} and {@code '\0'} for {@code char}. For non-primitive types and
   * {@code void}, {@code null} is returned.
   */
  @SuppressWarnings("unchecked")
  @CheckForNull
  public static <T> T defaultValue(Class<T> type) {
    checkNotNull(type);
    if (type.isPrimitive()) {
      if (type == boolean.class) {
        return (T) Boolean.FALSE;
      } else if (type == char.class) {

    assertEquals(false, Defaults.defaultValue(boolean.class).booleanValue());
    assertEquals('\0', Defaults.defaultValue(char.class).charValue());
    assertEquals(0, Defaults.defaultValue(byte.class).byteValue());
    assertEquals(0, Defaults.defaultValue(short.class).shortValue());
    assertEquals(0, Defaults.defaultValue(int.class).intValue());
    assertEquals(0, Defaults.defaultValue(long.class).longValue());

   * position}th position or {@code defaultValue} otherwise.
   *
   * @param position position of the element to return
   * @param defaultValue the default value to return if the iterator is empty or if {@code position}
   *     is greater than the number of elements remaining in {@code iterator}
   * @return the element at the specified position in {@code iterator} or {@code defaultValue} if

  }

  @Override
  public boolean isPresent() {
    return true;
  }

  @Override
  public T get() {
    return reference;
  }

  @Override
  public T or(T defaultValue) {
    checkNotNull(defaultValue, "use Optional.orNull() instead of Optional.or(null)");
    return reference;
  }

  @Override
  public Optional<T> or(Optional<? extends T> secondChoice) {
    checkNotNull(secondChoice);

  }

  @Override
  public boolean isPresent() {
    return true;
  }

  @Override
  public T get() {
    return reference;
  }

  @Override
  public T or(T defaultValue) {
    checkNotNull(defaultValue, "use Optional.orNull() instead of Optional.or(null)");
    return reference;
  }

  @Override
  public Optional<T> or(Optional<? extends T> secondChoice) {
    checkNotNull(secondChoice);

    @SuppressWarnings("unchecked") // Assume all default values are generics safe.
    T defaultValue = (T) defaultValues.getInstance(rawType);
    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // ArbitraryInstances always returns generics-safe dummies.
    T value = (T) ArbitraryInstances.get(rawType);
    if (value != null) {
      return value;
    }

  private static @Nullable Object getDefaultValue(final TypeToken<?> type) {
    Class<?> rawType = type.getRawType();
    Object defaultValue = ArbitraryInstances.get(rawType);
    if (defaultValue != null) {
      return defaultValue;
    }

    final String typeName = rawType.getCanonicalName();
    if (JUF_METHODS.containsKey(typeName)) {

  private static @Nullable Object getDefaultValue(final TypeToken<?> type) {
    Class<?> rawType = type.getRawType();
    Object defaultValue = ArbitraryInstances.get(rawType);
    if (defaultValue != null) {
      return defaultValue;
    }

    final String typeName = rawType.getCanonicalName();
    if (JUF_METHODS.containsKey(typeName)) {

    public V edgeValueOrDefault(N nodeU, N nodeV, @CheckForNull V defaultValue) {
      return delegate().edgeValueOrDefault(nodeV, nodeU, defaultValue); // transpose
    }

    @Override
    @CheckForNull
    public V edgeValueOrDefault(EndpointPair<N> endpoints, @CheckForNull V defaultValue) {
      return delegate().edgeValueOrDefault(transpose(endpoints), defaultValue);
    }
  }