### 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.

e.g., To scan objects stored under `user-uploads/` prefix and remove versions older than one year.

```
{
    "Rules": [

    super(key, value);
    this.cause = checkNotNull(cause);
  }

  /** Returns the cause for which the entry was removed. */
  public RemovalCause getCause() {
    return cause;
  }

  /**
   * Returns {@code true} if there was an automatic removal due to eviction (the cause is neither
   * {@link RemovalCause#EXPLICIT} nor {@link RemovalCause#REPLACED}).
   */
  public boolean wasEvicted() {

   * @param executor the executor with which removal notifications are asynchronously executed
   */
  public static <K, V> RemovalListener<K, V> asynchronous(
      RemovalListener<K, V> listener, Executor executor) {
    checkNotNull(listener);
    checkNotNull(executor);
    return (RemovalNotification<K, V> notification) ->
        executor.execute(() -> listener.onRemoval(notification));
  }

    // other operations, the cache and the removal queue won't change from this point on.

    // Verify that each received removal notification was valid
    for (RemovalNotification<String, String> notification : removalListener) {
      assertWithMessage("Invalid removal notification")
          .that(notification.getValue())
          .isEqualTo(notification.getKey());
    }

    // other operations, the cache and the removal queue won't change from this point on.

    // Verify that each received removal notification was valid
    for (RemovalNotification<String, String> notification : removalListener) {
      assertWithMessage("Invalid removal notification")
          .that(notification.getValue())
          .isEqualTo(notification.getKey());
    }

   * 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
   * the entry from the Map. If another operation sees a zero in the map, it knows that the entry is
   * about to be removed, so this operation may remove it (often by replacing it with a new
   * AtomicInteger).
   */

 */

package com.google.common.cache;

import com.google.common.annotations.GwtCompatible;

/**
 * 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.
 *

        classes['NewSub'].superclass = classes['NewBase']

        apiClass.compatibilityChanges >> [new JApiCompatibilityChange(JApiCompatibilityChangeType.METHOD_REMOVED_IN_SUPERCLASS)]
    }

    def "method removal can be reported if current class is first public class"() {
        given:
        apiClass.oldClass >> Optional.of(classes['OldBase'])
        apiClass.newClass >> Optional.of(classes['NewBase'])

        when:

   * 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
   * the entry from the Map. If another operation sees a zero in the map, it knows that the entry is
   * about to be removed, so this operation may remove it (often by replacing it with a new
   * AtomicInteger).
   */

   * Returns the next element in the iteration, without advancing the iteration.
   *
   * <p>Calls to {@code peek()} should not change the state of the iteration, except that it
   * <i>may</i> prevent removal of the most recent element via {@link #remove()}.
   *
   * @throws NoSuchElementException if the iteration has no more elements according to {@link
   *     #hasNext()}
   */
  @ParametricNullness
  E peek();

  /**