content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License. You may obtain a copy of the License at
   *
   *    http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.kafka.clients.admin;
  
  import org.apache.kafka.common.KafkaFuture;
  import org.apache.kafka.common.TopicCollection;
  import org.apache.kafka.common.Uuid;
  
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.concurrent.ExecutionException;
  
  /**
   * The result of the {@link KafkaAdminClient#describeTopics(Collection)} call.
   */
  public class DescribeTopicsResult {
      private final Map<Uuid, KafkaFuture<TopicDescription>> topicIdFutures;
      private final Map<String, KafkaFuture<TopicDescription>> nameFutures;
  
      // VisibleForTesting
      protected DescribeTopicsResult(Map<Uuid, KafkaFuture<TopicDescription>> topicIdFutures, Map<String, KafkaFuture<TopicDescription>> nameFutures) {
          if (topicIdFutures != null && nameFutures != null)
              throw new IllegalArgumentException("topicIdFutures and nameFutures cannot both be specified.");
          if (topicIdFutures == null && nameFutures == null)
              throw new IllegalArgumentException("topicIdFutures and nameFutures cannot both be null.");
          this.topicIdFutures = topicIdFutures;
          this.nameFutures = nameFutures;
      }
  
      static DescribeTopicsResult ofTopicIds(Map<Uuid, KafkaFuture<TopicDescription>> topicIdFutures) {
          return new DescribeTopicsResult(topicIdFutures, null);
      }
  
      static DescribeTopicsResult ofTopicNames(Map<String, KafkaFuture<TopicDescription>> nameFutures) {
          return new DescribeTopicsResult(null, nameFutures);
      }
  
      /**
       * Use when {@link Admin#describeTopics(TopicCollection, DescribeTopicsOptions)} used a TopicIdCollection
       *
       * @return a map from topic IDs to futures which can be used to check the status of
       *         individual topics if the request used topic IDs, otherwise return null.
       */
      public Map<Uuid, KafkaFuture<TopicDescription>> topicIdValues() {
          return topicIdFutures;
      }
  
      /**
       * Use when {@link Admin#describeTopics(TopicCollection, DescribeTopicsOptions)} used a TopicNameCollection
       *
       * @return a map from topic names to futures which can be used to check the status of
       *         individual topics if the request used topic names, otherwise return null.
       */
      public Map<String, KafkaFuture<TopicDescription>> topicNameValues() {
          return nameFutures;
      }
  
      /**
       * @return A future map from topic names to descriptions which can be used to check
       *         the status of individual description if the describe topic request used
       *         topic names, otherwise return null, this request succeeds only if all the
       *         topic descriptions succeed
       */
      public KafkaFuture<Map<String, TopicDescription>> allTopicNames() {
          return all(nameFutures);
      }
  
      /**
       * @return A future map from topic ids to descriptions which can be used to check the
       *         status of individual description if the describe topic request used topic
       *         ids, otherwise return null, this request succeeds only if all the topic
       *         descriptions succeed
       */
      public KafkaFuture<Map<Uuid, TopicDescription>> allTopicIds() {
          return all(topicIdFutures);
      }
  
      /**
       * Return a future which succeeds only if all the topic descriptions succeed.
       */
      private static <T> KafkaFuture<Map<T, TopicDescription>> all(Map<T, KafkaFuture<TopicDescription>> futures) {
          if (futures == null) return null;
          KafkaFuture<Void> future = KafkaFuture.allOf(futures.values().toArray(new KafkaFuture<?>[0]));
          return future.
              thenApply(v -> {
                  Map<T, TopicDescription> descriptions = new HashMap<>(futures.size());
                  for (Map.Entry<T, KafkaFuture<TopicDescription>> entry : futures.entrySet()) {
                      try {
                          descriptions.put(entry.getKey(), entry.getValue().get());
                      } catch (InterruptedException | ExecutionException e) {
                          // This should be unreachable, because allOf ensured that all the futures
                          // completed successfully.
                          throw new RuntimeException(e);
                      }
                  }
                  return descriptions;
              });
      }
  }
  