* value after the specified time has passed. Subsequent calls to {@code get()} return the cached
   * value if the expiration time has not passed. After the expiration time, a new value is
   * retrieved, cached, and returned. See: <a
   * href="http://en.wikipedia.org/wiki/Memoization">memoization</a>
   *

    }
    checkEviction(cchm);
    checkExpiration(cchm);
  }

  /**
   * Peeks into the cache's internals to verify that its expiration queue is consistent. Verifies
   * that the next/prev links in the expiration queue are correct, and that the queue is ordered by
   * expiration time.
   */
  static void checkExpiration(Cache<?, ?> cache) {
    if (hasLocalCache(cache)) {
      checkExpiration(toLocalCache(cache));

   * CacheBuilder#softValues}.
   */
  COLLECTED {
    @Override
    boolean wasEvicted() {
      return true;
    }
  },

  /**
   * The entry's expiration timestamp has passed. This can occur when using {@link
   * CacheBuilder#expireAfterWrite} or {@link CacheBuilder#expireAfterAccess}.
   */
  EXPIRED {
    @Override
    boolean wasEvicted() {
      return true;

 * never be removed.
 *
 * <p>Durations are represented by an integer, followed by one of "d", "h", "m", or "s",
 * representing days, hours, minutes, or seconds respectively. (There is currently no syntax to
 * request expiration in milliseconds, microseconds, or nanoseconds.)
 *
 * <p>Whitespace before and after commas and equal signs is ignored. Keys may not be repeated; it is
 * also illegal to use the following pairs of keys in a single value:
 *

    }
    checkEviction(cchm);
    checkExpiration(cchm);
  }

  /**
   * Peeks into the cache's internals to verify that its expiration queue is consistent. Verifies
   * that the next/prev links in the expiration queue are correct, and that the queue is ordered by
   * expiration time.
   */
  static void checkExpiration(Cache<?, ?> cache) {
    if (hasLocalCache(cache)) {
      checkExpiration(toLocalCache(cache));

 * An object that can receive a notification when an entry is removed from a cache. The removal
 * resulting in notification could have occurred to an entry being manually removed or replaced, or
 * due to eviction resulting from timed expiration, exceeding a maximum size, or garbage collection.
 *
 * <p>An instance may be called concurrently by multiple threads to process different entries.

   * CacheBuilder#softValues}.
   */
  COLLECTED {
    @Override
    boolean wasEvicted() {
      return true;
    }
  },

  /**
   * The entry's expiration timestamp has passed. This can occur when using {@link
   * CacheBuilder#expireAfterWrite} or {@link CacheBuilder#expireAfterAccess}.
   */
  EXPIRED {
    @Override
    boolean wasEvicted() {
      return true;

 * An object that can receive a notification when an entry is removed from a cache. The removal
 * resulting in notification could have occurred to an entry being manually removed or replaced, or
 * due to eviction resulting from timed expiration, exceeding a maximum size, or garbage collection.
 *
 * <p>An instance may be called concurrently by multiple threads to process different entries.

import java.util.Set;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import junit.framework.TestCase;

/**
 * Tests relating to cache expiration: make sure entries expire at the right times, make sure
 * expired entries don't show up, etc.
 *
 * @author mike nonemacher
 */
@SuppressWarnings("deprecation") // tests of deprecated method

      }
    };

    abstract Equivalence<Object> defaultEquivalence();
  }

  /**
   * Implementation for the EntryIterator, which is used to build Key and Value iterators.
   *
   * <p>Expiration is only checked on hasNext(), so as to ensure that a next() call never returns
   * null when hasNext() has already been called.
   */
  class EntryIterator implements Iterator<Entry<K, V>> {