if (childUrlSet != null) {
            // add an url
            try {
                storeChildUrls(childUrlSet.stream().filter(rd -> StringUtil.isNotBlank(rd.getUrl())).collect(Collectors.toSet()),
                        urlQueue.getUrl(), urlQueue.getDepth() != null ? urlQueue.getDepth() + 1 : 1);
            } catch (final Throwable t) {
                if (!ComponentUtil.available()) {

            }
            return result;
        }

        // After the collection we will have the artifact object in the result but they will not be resolved yet.
        result = artifactCollector.collect(
                artifacts, rootArtifact, managedVersions, collectionRequest, source, collectionFilter, listeners, null);

        // We have metadata retrieval problems, or there are cycles that have been detected

import com.google.common.base.Joiner;
import com.google.common.base.Optional;
import com.google.common.base.Predicate;
import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.graph.SuccessorsFunction;
import com.google.common.graph.Traverser;
import com.google.common.hash.HashCode;
import com.google.common.hash.HashFunction;

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.CollectPreconditions.checkNonnegative;
import static com.google.common.math.IntMath.sqrt;
import static java.lang.Math.max;

   *
   * @since 19.0
   */
  public static HashFunction concatenating(
      HashFunction first, HashFunction second, HashFunction... rest) {
    // We can't use Lists.asList() here because there's no hash->collect dependency
    List<HashFunction> list = new ArrayList<>();
    list.add(first);
    list.add(second);
    Collections.addAll(list, rest);
    return new ConcatenatedHashFunction(list.toArray(new HashFunction[0]));

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import static java.util.Arrays.asList;

import com.google.common.base.Joiner;
import com.google.common.collect.ImmutableMap;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.util.concurrent;

import com.google.common.collect.ObjectArrays;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.AbstractQueue;
import java.util.Collection;
import java.util.ConcurrentModificationException;
import java.util.Iterator;

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.CollectPreconditions.checkNonnegative;
import static com.google.common.math.IntMath.saturatedAdd;
import static java.lang.Math.max;

import com.google.common.base.Ticker;
import com.google.common.cache.TestingRemovalListeners.CountingRemovalListener;
import com.google.common.cache.TestingRemovalListeners.QueuingRemovalListener;
import com.google.common.collect.Sets;
import com.google.common.testing.NullPointerTester;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.time.Duration;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

import com.google.common.base.Ticker;
import com.google.common.cache.TestingRemovalListeners.CountingRemovalListener;
import com.google.common.cache.TestingRemovalListeners.QueuingRemovalListener;
import com.google.common.collect.Sets;
import com.google.common.testing.NullPointerTester;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.time.Duration;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;