### 3.1 Automatic removal of non current objects versions

A non-current object version is a version which is not the latest for a given object. It is possible to set up an automatic removal of non-current versions when a version becomes older than a given number of days.

  /*
   * The ConcurrentHashMultiset's atomic operations are implemented primarily in terms of
   * AtomicInteger's atomic operations, with some help from ConcurrentMap's atomic operations on
   * creation and removal (including automatic removal of zeroes). If the modification of an
   * AtomicInteger results in zero, we compareAndSet the value to zero; if that succeeds, we remove

    boolean removal = (maximumSize == LocalCache.UNSET_INT) ? false : (size() > maximumSize);
    if ((removalListener != null) && removal) {
      removalListener.onRemoval(
          RemovalNotification.create(
              ignored.getKey(), ignored.getValue().getValue(), RemovalCause.SIZE));
    }
    statsCounter.recordEviction();
    return removal;
  }

   * as necessary to try to ensure that this will happen.
   *
   * @throws RuntimeException if timed out or interrupted while waiting
   */
  @SuppressWarnings("removal") // b/487687332
  public static void awaitDone(Future<?> future) {
    if (future.isDone()) {
      return;
    }
    long timeoutSeconds = timeoutSeconds();

    private static final List<JApiCompatibilityChangeType> IGNORED_CHANGE_TYPES = ImmutableList.of(
        JApiCompatibilityChangeType.METHOD_REMOVED_IN_SUPERCLASS, // the removal of the method will be reported
        JApiCompatibilityChangeType.INTERFACE_REMOVED,            // the removed methods will be reported

   * into the cache. Newly loaded values are added to the cache using {@code
   * Cache.asMap().putIfAbsent} after loading has completed; if another value was associated with
   * {@code key} while the new value was loading then a removal notification will be sent for the
   * new value.
   *
   * <p>If the cache loader associated with this cache is known not to throw checked exceptions,
   * then prefer {@link #getUnchecked} over this method.
   *

 *   <li>Setting {@code maven.consumer.pom.flatten=true} removes them during transformation</li>
 *   <li>Otherwise, an exception is thrown requiring one of the above options or manual mixin removal</li>
 * </ul>
 * <p>
 * <b>Dependency Filtering</b>: For non-POM projects with dependency management, the builder:
 * <ul>
 *   <li>Filters dependencies to include only those with transitive scopes (compile/runtime)</li>

     */
    SHARE_MOVE(3),

    /**
     * IP address changed - network configuration change
     */
    IP_CHANGE(4),

    /**
     * Share deleted - share removal notification
     */
    SHARE_DELETE(5),

    /**
     * Cluster node unavailable - node down event
     */
    NODE_UNAVAILABLE(6),

    /**
     * Cluster node available - node up event
     */

### Expiry or removal events

    long blah = 0;
    for (int i = 0; i < reps; i++) {
      Integer key = keys.get(random.nextInt(nKeys));
      // This range is [-5, 4] - slight negative bias so we often hit zero, which brings the
      // auto-removal of zeroes into play.
      int delta = random.nextInt(10) - 5;
      blah += delta;
      if (delta >= 0) {
        multiset.add(key, delta);
      } else {
        multiset.remove(key, -delta);
      }