switch (size()) {
      case 0:
        return ImmutableList.of();
      case 1:
        return ImmutableList.of(iterator().next());
      default:
        return new RegularImmutableAsList<E>(this, toArray());
    }
  }

  /** If this collection is backed by an array of its elements in insertion order, returns it. */
  Object @Nullable [] internalArray() {
    return null;
  }

  /**

                    groupList.size(), roleList.size(), groupIdsForParentLookup.size());
        }

        // Set initial groups
        user.setGroups(groupList.stream().distinct().toArray(n -> new String[n]));
        user.setRoles(roleList.stream().distinct().toArray(n -> new String[n]));

        if (logger.isDebugEnabled()) {
            logger.debug("[updateMemberOf] Initial groups/roles set for user: {}. Groups: {}, Roles: {}", user.getName(),

     *
     * @return an array of all unique file type values
     */
    public String[] getTypes() {
        return mimetypeMap.values().stream().distinct().toArray(n -> new String[n]);
    }

            field = StreamUtil.split(fessConfig.getQueryFacetFields(), ",")
                    .get(stream -> stream.map(String::trim).filter(StringUtil::isNotEmpty).distinct().toArray(n -> new String[n]));
        }
        if (StringUtil.isNotBlank(fessConfig.getQueryFacetFieldsSize())) {
            size = fessConfig.getQueryFacetFieldsSizeAsInteger();
        }

    if (elements.isEmpty()) {
      // We avoid allocating anything.
      return of();
    }
    // Collection<E>.toArray() is required to contain only E instances, and all we do is read them.
    // TODO(cpovirk): Consider using Object[] anyway.
    @SuppressWarnings("unchecked")
    E[] array = (E[]) elements.toArray();
    /*
     * For a Set, we guess that it contains no duplicates. That's just a guess for purpose of

            }
        }

        final String[] hosts = split(ResourceUtil.getFesenHttpUrl(), ",")
                .get(stream -> stream.map(String::trim).filter(StringUtil::isNotEmpty).toArray(n -> new String[n]));
        nodeManager = new NodeManager(hosts, node -> request(new CurlRequest(Method.GET, node.getUrl("/"))));
        nodeManager.setHeartbeatInterval(fessConfig.getFesenHeartbeatInterval());
    }

  public static <T extends @Nullable Object> T[] toArray(
      Iterable<? extends T> iterable, Class<@NonNull T> type) {
    return toArray(iterable, ObjectArrays.newArray(type, 0));
  }

  static <T extends @Nullable Object> T[] toArray(Iterable<? extends T> iterable, T[] array) {
    Collection<? extends T> collection = castOrCopyToCollection(iterable);
    return collection.toArray(array);
  }

  /**

        final String targets = System.getProperty(TARGET_INDICES);
        if (StringUtil.isNotBlank(targets)) {
            targetIndices = Arrays.stream(targets.split(",")).map(String::trim).toArray(n -> new String[n]);
        }
    }

    /**
     * Sets the address of the OpenSearch instance.
     * @param address The address.
     */
    public void setAddress(final String address) {

      } catch (UnsupportedOperationException expected) {
      }

      try {
        ((Collection<?>) multimap.asMap().values().toArray()[0]).clear();
        fail("asMap().values().toArray()[0].clear() succeeded on unmodifiable multimap");
      } catch (UnsupportedOperationException expected) {
      }
    }

    assertCollectionIsUnmodifiable(multimap.values(), sampleValue);

        return split(permissionsText, "\n")
                .get(stream -> stream.map(permissionHelper::encode).filter(StringUtil::isNotBlank).distinct().toArray(String[]::new));
    }

    // ===================================================================================
    //                                                                            Document