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.image;
  
  import org.apache.kafka.common.Uuid;
  import org.apache.kafka.image.node.TopicsImageByNameNode;
  import org.apache.kafka.image.writer.ImageWriter;
  import org.apache.kafka.image.writer.ImageWriterOptions;
  import org.apache.kafka.metadata.PartitionRegistration;
  import org.apache.kafka.server.immutable.ImmutableMap;
  import org.apache.kafka.server.util.TranslatedValueMapView;
  
  import java.util.Map;
  import java.util.Objects;
  
  /**
   * Represents the topics in the metadata image.
   *
   * This class is thread-safe.
   */
  public final class TopicsImage {
      public static final TopicsImage EMPTY =  new TopicsImage(ImmutableMap.empty(), ImmutableMap.empty());
  
      private final ImmutableMap<Uuid, TopicImage> topicsById;
      private final ImmutableMap<String, TopicImage> topicsByName;
  
      public TopicsImage(
          ImmutableMap<Uuid, TopicImage> topicsById,
          ImmutableMap<String, TopicImage> topicsByName
      ) {
          this.topicsById = topicsById;
          this.topicsByName = topicsByName;
      }
  
      public TopicsImage including(TopicImage topic) {
          return new TopicsImage(
              this.topicsById.updated(topic.id(), topic),
              this.topicsByName.updated(topic.name(), topic));
      }
  
      public boolean isEmpty() {
          return topicsById.isEmpty() && topicsByName.isEmpty();
      }
  
      public ImmutableMap<Uuid, TopicImage> topicsById() {
          return topicsById;
      }
  
      public ImmutableMap<String, TopicImage> topicsByName() {
          return topicsByName;
      }
  
      public PartitionRegistration getPartition(Uuid id, int partitionId) {
          TopicImage topicImage = topicsById.get(id);
          if (topicImage == null) return null;
          return topicImage.partitions().get(partitionId);
      }
  
      public TopicImage getTopic(Uuid id) {
          return topicsById.get(id);
      }
  
      public TopicImage getTopic(String name) {
          return topicsByName.get(name);
      }
  
      public void write(ImageWriter writer, ImageWriterOptions options) {
          for (Map.Entry<Uuid, TopicImage> entry : topicsById.entrySet()) {
              entry.getValue().write(writer, options);
          }
      }
  
      @Override
      public boolean equals(Object o) {
          if (!(o instanceof TopicsImage other)) return false;
          return topicsById.equals(other.topicsById) &&
              topicsByName.equals(other.topicsByName);
      }
  
      @Override
      public int hashCode() {
          return Objects.hash(topicsById, topicsByName);
      }
  
      /**
       * Expose a view of this TopicsImage as a map from topic names to IDs.
       *
       * Like TopicsImage itself, this map is immutable.
       */
      public Map<String, Uuid> topicNameToIdView() {
          return new TranslatedValueMapView<>(topicsByName, TopicImage::id);
      }
  
      /**
       * Expose a view of this TopicsImage as a map from IDs to names.
       *
       * Like TopicsImage itself, this map is immutable.
       */
      public Map<Uuid, String> topicIdToNameView() {
          return new TranslatedValueMapView<>(topicsById, TopicImage::name);
      }
  
      @Override
      public String toString() {
          return new TopicsImageByNameNode(this).stringify();
      }
  }
  