CacheLoader<Integer, String> recursiveLoader =
        new CacheLoader<Integer, String>() {
          @Override
          public String load(Integer key) {
            if (key > 0) {
              return key + ", " + cacheRef.get().getUnchecked(key - 1);
            } else {
              return "0";
            }
          }
        };

    LoadingCache<Integer, String> recursiveCache =

    CacheLoader<Integer, String> recursiveLoader =
        new CacheLoader<Integer, String>() {
          @Override
          public String load(Integer key) {
            if (key > 0) {
              return key + ", " + cacheRef.get().getUnchecked(key - 1);
            } else {
              return "0";
            }
          }
        };

    LoadingCache<Integer, String> recursiveCache =

    }

    /**
     * Returns the key.
     *
     * @return the key
     */
    public String getKey() {
        return key;
    }

    /**
     * Sets the key.
     *
     * @param key
     *            the key
     */
    public void setKey(final String key) {
        this.key = key;
    }

    /**
     * Returns the charset name.
     *

  }

  @Override
  public @Nullable Entry<K, V> floorEntry(K key) {
    return delegate.floorEntry(checkValid(key));
  }

  @Override
  public @Nullable K floorKey(K key) {
    return delegate.floorKey(checkValid(key));
  }

  @Override
  public @Nullable V get(Object key) {
    return delegate.get(checkValid(key));
  }

  @Override
  public SortedMap<K, V> headMap(K toKey) {

        RenderDataUtil.register(data, "key1", null);
        assertNull(data.getDataMap().get("key1"));
    }

    @Test
    public void test_register_string() {
        RenderData data = new RenderData();
        RenderDataUtil.register(data, "key1", "test value");
        assertEquals("test value", data.getDataMap().get("key1"));

        RenderDataUtil.register(data, "key2", "");

        }
        return asMap;
      }
    }

    @Override
    public Multiset<K> keys() {
      synchronized (mutex) {
        if (keys == null) {
          keys = multiset(delegate().keys(), mutex);
        }
        return keys;
      }
    }

    @Override
    // A forwarding implementation can't do any better than the underlying object.

   * equal.
   */
  boolean areEqual();

  /**
   * Returns an unmodifiable map containing the entries from the left map whose keys are not present
   * in the right map.
   */
  Map<K, V> entriesOnlyOnLeft();

  /**
   * Returns an unmodifiable map containing the entries from the right map whose keys are not
   * present in the left map.
   */
  Map<K, V> entriesOnlyOnRight();

  /**

 *
 * {@snippet :
 * LoadingCache<Key, Graph> graphs = CacheBuilder.newBuilder()
 *     .maximumSize(10000)
 *     .expireAfterWrite(Duration.ofMinutes(10))
 *     .removalListener(MY_LISTENER)
 *     .build(
 *         new CacheLoader<Key, Graph>() {
 *           public Graph load(Key key) throws AnyException {
 *             return createExpensiveGraph(key);
 *           }
 *         });
 * }
 *

    if (oldNodeForValue != null
        && keyHash == oldNodeForValue.keyHash
        && Objects.equals(key, oldNodeForValue.key)) {
      return key;
    } else if (oldNodeForKey != null && !force) {
      throw new IllegalArgumentException("key already present: " + key);
    }

    if (oldNodeForValue != null) {
      delete(oldNodeForValue);
    }

 * shared resources.
 *
 * @param <K> the most general type of keys this listener can listen for; for example {@code Object}
 *     if any key is acceptable
 * @param <V> the most general type of values this listener can listen for; for example {@code
 *     Object} if any key is acceptable
 * @author Charles Fry
 * @since 10.0
 */
@GwtCompatible
public interface RemovalListener<K, V> {