* @param event the event that could not be delivered.
   */
  public DeadEvent(Object source, Object event) {
    this.source = checkNotNull(source);
    this.event = checkNotNull(event);
  }

  /**
   * Returns the object that originated this event (not the object that originated the
   * wrapped event). This is generally an {@link EventBus}.
   *

 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.common.util.concurrent;

import static com.google.common.base.Preconditions.checkNotNull;
import static java.lang.Thread.currentThread;

import com.google.common.annotations.GwtCompatible;
import javax.annotation.CheckForNull;

/** Methods factored out so that they can be emulated differently in GWT. */

 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.common.util.concurrent;

import static com.google.common.base.Preconditions.checkNotNull;
import static java.lang.Thread.currentThread;

import com.google.common.annotations.GwtCompatible;
import javax.annotation.CheckForNull;

/** Methods factored out so that they can be emulated differently in GWT. */

        /* userPassedSupplier= */ false);
  }

  private static <T extends Throwable> T doAssertThrows(
      Class<T> expectedThrowable, ThrowingSupplier supplier, boolean userPassedSupplier) {
    checkNotNull(expectedThrowable);
    checkNotNull(supplier);
    Predicate<Throwable> predicate = INSTANCE_OF.get(expectedThrowable);
    if (predicate == null) {
      throw new IllegalArgumentException(
          expectedThrowable

        /* userPassedSupplier= */ false);
  }

  private static <T extends Throwable> T doAssertThrows(
      Class<T> expectedThrowable, ThrowingSupplier supplier, boolean userPassedSupplier) {
    checkNotNull(expectedThrowable);
    checkNotNull(supplier);
    Predicate<Throwable> predicate = INSTANCE_OF.get(expectedThrowable);
    if (predicate == null) {
      throw new IllegalArgumentException(
          expectedThrowable

        /* userPassedSupplier= */ false);
  }

  private static <T extends Throwable> T doAssertThrows(
      Class<T> expectedThrowable, ThrowingSupplier supplier, boolean userPassedSupplier) {
    checkNotNull(expectedThrowable);
    checkNotNull(supplier);
    Predicate<Throwable> predicate = INSTANCE_OF.get(expectedThrowable);
    if (predicate == null) {
      throw new IllegalArgumentException(
          expectedThrowable

        /* userPassedSupplier= */ false);
  }

  private static <T extends Throwable> T doAssertThrows(
      Class<T> expectedThrowable, ThrowingSupplier supplier, boolean userPassedSupplier) {
    checkNotNull(expectedThrowable);
    checkNotNull(supplier);
    Predicate<Throwable> predicate = INSTANCE_OF.get(expectedThrowable);
    if (predicate == null) {
      throw new IllegalArgumentException(
          expectedThrowable

        /* userPassedSupplier= */ false);
  }

  private static <T extends Throwable> T doAssertThrows(
      Class<T> expectedThrowable, ThrowingSupplier supplier, boolean userPassedSupplier) {
    checkNotNull(expectedThrowable);
    checkNotNull(supplier);
    Predicate<Throwable> predicate = INSTANCE_OF.get(expectedThrowable);
    if (predicate == null) {
      throw new IllegalArgumentException(
          expectedThrowable

  /** Returns a - b, guaranteed that both arguments are nonnegative. */
  abstract X minus(X a, X b);

  /** Rounds {@code x} to a {@code double}. */
  final double roundToDouble(X x, RoundingMode mode) {
    checkNotNull(x, "x");
    checkNotNull(mode, "mode");
    double roundArbitrarily = roundToDoubleArbitrarily(x);
    if (Double.isInfinite(roundArbitrarily)) {
      switch (mode) {
        case DOWN:
        case HALF_EVEN:

      cachingHashMap.remove(key);
      return null;
    }
  }

  @CanIgnoreReturnValue
  @Override
  public V put(K key, V value) {
    checkNotNull(key);
    checkNotNull(value);
    Timestamped<V> oldValue = cachingHashMap.put(key, new Timestamped<V>(value, ticker));
    if (oldValue == null) {
      return null;
    }