* <td>{@link #base64()}
 * <td>A-Z a-z 0-9 + /
 * <td>1.33
 * <td>=
 * <td>
 * <tr>
 * <td>{@link #base64Url()}
 * <td>A-Z a-z 0-9 - _
 * <td>1.33
 * <td>=
 * <td>Safe to use as filenames, or to pass in URLs without escaping
 * </table>
 *
 * <p>All instances of this class are immutable, so they may be stored safely as static constants.
 *
 * @author Louis Wasserman
 * @since 14.0
 */

 * for that key. The subclass should not call {@link #createCollection()} directly, and a new
 * instance should be created every time the method is called.
 *
 * <p>For example, the subclass could pass a {@link java.util.TreeMap} during construction, and
 * {@link #createCollection()} could return a {@link java.util.TreeSet}, in which case the
 * multimap's iterators would propagate through the keys and values in sorted order.
 *

        }
      };
    }

    private static final long serialVersionUID = 0;
  }

  /**
   * Implementation of a transforming random access list. We try to make as many of these methods
   * pass-through to the source list as possible so that the performance characteristics of the
   * source list and transformed list are similar.
   *
   * @see Lists#transform
   */

          // We unwind setFuture specifically to avoid StackOverflowErrors in the case of long
          // chains of SetFutures
          // Handling this special case is important because there is no way to pass an executor to
          // setFuture, so a user couldn't break the chain by doing this themselves.  It is also
          // potentially common if someone writes a recursive Futures.transformAsync transformer.

    combiner = null;
    // combiner should be collected even if the future it returns never completes.
    GcFinalization.awaitClear(combinerRef);
  }

  /*
   * TODO(cpovirk): maybe pass around TestFuture instances instead of
   * ListenableFuture instances
   */

  /**
   * A future in {@link TestFutureBatch} that also has a name for debugging purposes and a {@code

   * dummy version.
   *
   * @throws UnsupportedOperationException always
   * @deprecated <b>Pass a parameter of type {@code Comparable} to use {@link
   *     ImmutableSortedSet#of(Comparable)}.</b>
   */
  @DoNotCall("Pass a parameter of type Comparable")
  @Deprecated
  public static <E> ImmutableSortedSet<E> of(E element) {
    throw new UnsupportedOperationException();
  }

    } catch (IllegalArgumentException e) {
      // pass
    }
    assertEquals("<lo><hi>", charEscaper.escape("\uDC00\uD800"));
    try {
      unicodeEscaper.escape("\uDC00\uD800");
      fail("should have failed for bad Unicode input");
    } catch (IllegalArgumentException e) {
      // pass
    }
  }

  // A trivial non-optimized escaper for testing.

  }

  /**
   * Wrapper for {@link Map#get(Object)} that forces the caller to pass in a key of the same type as
   * the map. Besides being slightly shorter than code that uses {@link #getMap()}, it also ensures
   * that callers don't pass an {@link Entry} by mistake.
   */
  protected V get(K key) {
    return getMap().get(key);
  }

  protected final K k0() {

    return delegate().apply(key);
  }

  @Override
  public void refresh(K key) {
    delegate().refresh(key);
  }

  /**
   * A simplified version of {@link ForwardingLoadingCache} where subclasses can pass in an already
   * constructed {@link LoadingCache} as the delegate.
   *
   * @since 10.0
   */
  public abstract static class SimpleForwardingLoadingCache<K, V>
      extends ForwardingLoadingCache<K, V> {

    Iterator<Integer> iter =
        new AbstractIterator<Integer>() {
          @Override
          public Integer computeNext() {
            throw exception;
          }
        };

    // It should pass through untouched
    try {
      iter.hasNext();
      fail("No exception thrown");
    } catch (SomeUncheckedException e) {
      assertSame(exception, e);
    }
  }