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.clients.admin.internals.CoordinatorKey;
  import org.apache.kafka.clients.consumer.OffsetAndMetadata;
  import org.apache.kafka.common.KafkaFuture;
  import org.apache.kafka.common.TopicPartition;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.concurrent.ExecutionException;
  import java.util.stream.Collectors;
  
  /**
   * The result of the {@link Admin#listConsumerGroupOffsets(Map)} and
   * {@link Admin#listConsumerGroupOffsets(String)} call.
   * <p>
   */
  public class ListConsumerGroupOffsetsResult {
  
      final Map<String, KafkaFuture<Map<TopicPartition, OffsetAndMetadata>>> futures;
  
      ListConsumerGroupOffsetsResult(final Map<CoordinatorKey, KafkaFuture<Map<TopicPartition, OffsetAndMetadata>>> futures) {
          this.futures = futures.entrySet().stream()
                  .collect(Collectors.toMap(e -> e.getKey().idValue, Entry::getValue));
      }
  
      /**
       * Return a future which yields a map of topic partitions to OffsetAndMetadata objects.
       * If the group does not have a committed offset for this partition, the corresponding value in the returned map will be null.
       */
      public KafkaFuture<Map<TopicPartition, OffsetAndMetadata>> partitionsToOffsetAndMetadata() {
          if (futures.size() != 1) {
              throw new IllegalStateException("Offsets from multiple consumer groups were requested. " +
                      "Use partitionsToOffsetAndMetadata(groupId) instead to get future for a specific group.");
          }
          return futures.values().iterator().next();
      }
  
      /**
       * Return a future which yields a map of topic partitions to OffsetAndMetadata objects for
       * the specified group. If the group doesn't have a committed offset for a specific
       * partition, the corresponding value in the returned map will be null.
       */
      public KafkaFuture<Map<TopicPartition, OffsetAndMetadata>> partitionsToOffsetAndMetadata(String groupId) {
          if (!futures.containsKey(groupId))
              throw new IllegalArgumentException("Offsets for consumer group '" + groupId + "' were not requested.");
          return futures.get(groupId);
      }
  
      /**
       * Return a future which yields all {@code Map<String, Map<TopicPartition, OffsetAndMetadata>} objects,
       * if requests for all the groups succeed.
       */
      public KafkaFuture<Map<String, Map<TopicPartition, OffsetAndMetadata>>> all() {
          return KafkaFuture.allOf(futures.values().toArray(new KafkaFuture<?>[0])).thenApply(
              nil -> {
                  Map<String, Map<TopicPartition, OffsetAndMetadata>> listedConsumerGroupOffsets = new HashMap<>(futures.size());
                  futures.forEach((key, future) -> {
                      try {
                          listedConsumerGroupOffsets.put(key, future.get());
                      } catch (InterruptedException | ExecutionException e) {
                          // This should be unreachable, since the KafkaFuture#allOf already ensured
                          // that all of the futures completed successfully.
                          throw new RuntimeException(e);
                      }
                  });
                  return listedConsumerGroupOffsets;
              });
      }
  }
  