}

  @Override
  Map<K, Collection<V>> createAsMap() {
    return new AsMap();
  }

  @Override
  Set<K> createKeySet() {
    return asMap().keySet();
  }

  boolean removeEntriesIf(Predicate<? super Entry<K, Collection<V>>> predicate) {
    Iterator<Entry<K, Collection<V>>> entryIterator = unfiltered.asMap().entrySet().iterator();
    boolean changed = false;

        Set<?> set = (Set<?>) obj;
        return inputSet.keySet().containsAll(set);
      }
      return false;
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      if (obj instanceof PowerSet) {
        PowerSet<?> that = (PowerSet<?>) obj;
        return inputSet.keySet().equals(that.inputSet.keySet());
      }
      return super.equals(obj);
    }

    Multimap<String, Integer> map = create();
    map.put("bar", 1);
    map.put("foo", 2);
    map.put("bar", 3);
    map.put("bar", 4);
    assertEquals("[bar, foo]", map.keySet().toString());
    map.keySet().remove("bar");
    assertEquals("{foo=[2]}", map.toString());
  }

  public void testLinkedKeys() {
    Multimap<String, Integer> map = create();
    map.put("bar", 1);
    map.put("foo", 2);

     *
     * @param cmdList the command list to add properties to
     */
    protected void addFessConfigProperties(final List<String> cmdList) {
        System.getProperties()
                .keySet()
                .stream()
                .filter(k -> k != null && k.toString().startsWith(Constants.FESS_CONFIG_PREFIX))
                .forEach(k -> addSystemProperty(cmdList, k.toString(), null, null));
    }

    }

    /**
     * Returns a Set view of the keys contained in this map.
     *
     * @return a set view of the keys contained in this map
     */
    @Override
    public Set<String> keySet() {
        return parent.keySet();
    }

    /**
     * Returns a Collection view of the values contained in this map.
     *
     * @return a collection view of the values contained in this map
     */
    @Override

      Set<K> keySet = new HashSet<>();
      List<Entry<K, V>> builder = new ArrayList<>();
      for (Object o : elements) {
        Entry<?, ?> entry = (Entry<?, ?>) o;
        // These come from Entry<K, Collection<V>>> objects somewhere.
        @SuppressWarnings("unchecked")
        K key = (K) entry.getKey();
        keySet.add(key);

  public void testSameComparator() {
    assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Sets.newTreeSet()));
    assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Maps.newTreeMap().keySet()));
    assertTrue(
        SortedIterables.hasSameComparator(
            Ordering.natural().reverse(), Sets.newTreeSet(Ordering.natural().reverse())));
  }

  public void testComparator() {

            for (String extension : checksums.keySet()) {
                ChecksumObserver observer = checksums.get(extension);
                sums.put(extension, observer.getActualChecksum());
            }

            // We do this in here so we can checksum the artifact metadata too, otherwise it could be metadata itself
            for (String extension : checksums.keySet()) {

            putAll(map);
        }
    }

    @Override
    public String toString() {
        StringBuilder buffer = new StringBuilder("ManagedVersionMap (" + size() + " entries)\n");
        Iterator<String> iter = keySet().iterator();
        while (iter.hasNext()) {
            String key = iter.next();
            buffer.append(key).append('=').append(get(key));
            if (iter.hasNext()) {
                buffer.append('\n');

    // Each of the values added to the map should either still be there, or have seen a removal
    // notification.
    assertEquals(expectedKeys, Sets.union(cache.asMap().keySet(), removalNotifications.keySet()));
    assertTrue(Sets.intersection(cache.asMap().keySet(), removalNotifications.keySet()).isEmpty());
    threadPool.shutdown();
    threadPool.awaitTermination(300, SECONDS);
  }

  /**