* @since 17.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Verify {
  /**
   * Ensures that {@code expression} is {@code true}, throwing a {@code VerifyException} with no
   * message otherwise.
   *
   * @throws VerifyException if {@code expression} is {@code false}
   * @see Preconditions#checkState Preconditions.checkState()
   */
  public static void verify(boolean expression) {
    if (!expression) {

  /**
   * Returns the value associated with {@code key} in this cache, obtaining that value from {@code
   * loader} if necessary. The method improves upon the conventional "if cached, return; otherwise
   * create, cache and return" pattern. For further improvements, use {@link LoadingCache} and its
   * {@link LoadingCache#get(Object) get(K)} method instead of this one.
   *

   * Returns the string if it is not null, or an empty string otherwise.
   *
   * @param string the string to test and possibly return
   * @return {@code string} if it is not null; {@code ""} otherwise
   */
  static String nullToEmpty(@CheckForNull String string) {
    return (string == null) ? "" : string;
  }

  /**
   * Returns the string if it is not empty, or a null string otherwise.
   *

 * the License.
 */

package com.google.common.annotations;

/**
 * Annotates a program element that exists, or is more widely visible than otherwise necessary, only
 * for use in test code.
 *
 * <p><b>Do not use this interface</b> for public or protected declarations: it is a fig leaf for

   *
   * @param timeout the maximum time to wait for the permit. Negative values are treated as zero.
   * @param unit the time unit of the timeout argument
   * @return {@code true} if the permit was acquired, {@code false} otherwise
   * @throws IllegalArgumentException if the requested number of permits is negative or zero
   */
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration

   */
  @SuppressWarnings("ShortCircuitBoolean")
  public static boolean isPowerOfTwo(long x) {
    return x > 0 & (x & (x - 1)) == 0;
  }

  /**
   * Returns 1 if {@code x < y} as unsigned longs, and 0 otherwise. Assumes that x - y fits into a
   * signed long. The implementation is branch-free, and benchmarks suggest it is measurably faster
   * than the straightforward ternary expression.
   */
  @VisibleForTesting

   *
   * <p>If a code point has no mapped replacement then it is checked against the safe range. If it
   * lies outside that, then {@link #escapeUnsafe} is called, otherwise no escaping is performed.
   *
   * @param replacementMap a map of characters to their escaped representations
   * @param safeMin the lowest character value in the safe range

      for any such Derivative Works as a whole, provided Your use,
      reproduction, and distribution of the Work otherwise complies with
      the conditions stated in this License.

   5. Submission of Contributions. Unless You explicitly state otherwise,
      any Contribution intentionally submitted for inclusion in the Work
      by You to the Licensor shall be under the terms and conditions of

        fail("mismatch at index " + i + ": " + reportContext(expectedList));
      }
    }
  }

  /**
   * Used to delay string formatting until actually required, as it otherwise shows up in the test
   * execution profile when running an extremely large numbers of tests.
   */
  private String reportContext(List<E> expected) {
    return Platform.format(

    return new Present<>(checkNotNull(reference));
  }

  /**
   * If {@code nullableReference} is non-null, returns an {@code Optional} instance containing that
   * reference; otherwise returns {@link Optional#absent}.
   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> this method is equivalent to Java 8's
   * {@code Optional.ofNullable}.
   */