assertThrows(IllegalArgumentException.class, () -> builder.refreshAfterWrite(Duration.ZERO));
  }

  @GwtIncompatible // refreshAfterWrite
  public void testRefresh_setTwice() {
    CacheBuilder<Object, Object> builder =
        CacheBuilder.newBuilder().refreshAfterWrite(3600, SECONDS);
    assertThrows(IllegalStateException.class, () -> builder.refreshAfterWrite(3600, SECONDS));
  }

  @GwtIncompatible // Duration

    assertThrows(IllegalArgumentException.class, () -> builder.refreshAfterWrite(Duration.ZERO));
  }

  @GwtIncompatible // refreshAfterWrite
  public void testRefresh_setTwice() {
    CacheBuilder<Object, Object> builder =
        CacheBuilder.newBuilder().refreshAfterWrite(3600, SECONDS);
    assertThrows(IllegalStateException.class, () -> builder.refreshAfterWrite(3600, SECONDS));
  }

  @GwtIncompatible // Duration

  @IgnoreJRERequirement // No more dangerous than wherever the caller got the Duration from
  @CanIgnoreReturnValue
  public CacheBuilder<K, V> refreshAfterWrite(Duration duration) {
    return refreshAfterWrite(toNanosSaturated(duration), NANOSECONDS);
  }

  /**
   * Specifies that active entries are eligible for automatic refresh once a fixed duration has

  public void testAutoRefresh() {
    FakeTicker ticker = new FakeTicker();
    IncrementingLoader loader = incrementingLoader();
    LoadingCache<Integer, Integer> cache =
        CacheBuilder.newBuilder()
            .refreshAfterWrite(3, MILLISECONDS)
            .expireAfterWrite(6, MILLISECONDS)
            .lenientParsing()
            .ticker(ticker)
            .build(loader);
    int expectedLoads = 0;
    int expectedReloads = 0;

   * method is called when an existing cache entry is refreshed by {@link
   * CacheBuilder#refreshAfterWrite}, or through a call to {@link LoadingCache#refresh}.
   *
   * <p>This implementation synchronously delegates to {@link #load}. It is recommended that it be
   * overridden with an asynchronous implementation when using {@link
   * CacheBuilder#refreshAfterWrite}.
   *

  public void testAutoRefresh() {
    FakeTicker ticker = new FakeTicker();
    IncrementingLoader loader = incrementingLoader();
    LoadingCache<Integer, Integer> cache =
        CacheBuilder.newBuilder()
            .refreshAfterWrite(3, MILLISECONDS)
            .expireAfterWrite(6, MILLISECONDS)
            .lenientParsing()
            .ticker(ticker)
            .build(loader);
    int expectedLoads = 0;
    int expectedReloads = 0;

   *       authoritative location}
   *   <li>{@linkplain LoadingCache#refresh refreshing of entries}, including {@linkplain
   *       CacheBuilder#refreshAfterWrite automated refreshing}
   *   <li>{@linkplain LoadingCache#getAll bulk loading requests}, including {@linkplain
   *       CacheLoader#loadAll bulk loading implementations}
   * </ul>
   *

          }
        };

    LoadingCache<Object, Object> cache =
        CacheBuilder.newBuilder()
            .recordStats()
            .ticker(ticker)
            .refreshAfterWrite(1, MILLISECONDS)
            .build(loader);
    Object key = new Object();
    CacheStats stats = cache.stats();
    assertEquals(0, stats.missCount());
    assertEquals(0, stats.loadSuccessCount());

    }
    if (expireAfterAccess != null) {
      builder.expireAfterAccess(expireAfterAccess.duration, expireAfterAccess.unit);
    }
    if (refresh != null) {
      builder.refreshAfterWrite(refresh.duration, refresh.unit);
    }
    if (keyStrength != null) {
      builder.setKeyStrength(keyStrength);
    }
    if (valueStrength != null) {
      builder.setValueStrength(valueStrength);
    }

   *       authoritative location}
   *   <li>{@linkplain LoadingCache#refresh refreshing of entries}, including {@linkplain
   *       CacheBuilder#refreshAfterWrite automated refreshing}
   *   <li>{@linkplain LoadingCache#getAll bulk loading requests}, including {@linkplain
   *       CacheLoader#loadAll bulk loading implementations}
   * </ul>
   *