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.config.ConfigResource;
  import org.apache.kafka.common.config.ConfigResource.Type;
  import org.apache.kafka.common.metadata.ConfigRecord;
  import org.apache.kafka.common.metadata.RemoveTopicRecord;
  import org.apache.kafka.server.common.MetadataVersion;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Map.Entry;
  
  
  /**
   * Represents changes to the configurations in the metadata image.
   */
  public final class ConfigurationsDelta {
      private final ConfigurationsImage image;
      private final Map<ConfigResource, ConfigurationDelta> changes = new HashMap<>();
  
      public ConfigurationsDelta(ConfigurationsImage image) {
          this.image = image;
      }
  
      public Map<ConfigResource, ConfigurationDelta> changes() {
          return changes;
      }
  
      public void finishSnapshot() {
          for (Entry<ConfigResource, ConfigurationImage> entry : image.resourceData().entrySet()) {
              ConfigResource resource = entry.getKey();
              ConfigurationImage configImage = entry.getValue();
              ConfigurationDelta configDelta = changes.computeIfAbsent(resource,
                  __ -> new ConfigurationDelta(configImage));
              configDelta.finishSnapshot();
          }
      }
  
      public void handleMetadataVersionChange(MetadataVersion newVersion) {
          // no-op
      }
  
      public void replay(ConfigRecord record) {
          ConfigResource resource =
              new ConfigResource(Type.forId(record.resourceType()), record.resourceName());
          ConfigurationImage configImage = image.resourceData().getOrDefault(resource,
                  new ConfigurationImage(resource, Map.of()));
          ConfigurationDelta delta = changes.computeIfAbsent(resource,
              __ -> new ConfigurationDelta(configImage));
          delta.replay(record);
      }
  
      public void replay(RemoveTopicRecord record, String topicName) {
          ConfigResource resource =
              new ConfigResource(Type.TOPIC, topicName);
          if (image.resourceData().containsKey(resource)) {
              ConfigurationImage configImage = image.resourceData().get(resource);
              ConfigurationDelta delta = changes.computeIfAbsent(resource,
                  __ -> new ConfigurationDelta(configImage));
              delta.deleteAll();
          }
      }
  
      public ConfigurationsImage apply() {
          Map<ConfigResource, ConfigurationImage> newData = new HashMap<>();
          for (Entry<ConfigResource, ConfigurationImage> entry : image.resourceData().entrySet()) {
              ConfigResource resource = entry.getKey();
              ConfigurationDelta delta = changes.get(resource);
              if (delta == null) {
                  newData.put(resource, entry.getValue());
              } else {
                  ConfigurationImage newImage = delta.apply();
                  if (!newImage.isEmpty()) {
                      newData.put(resource, newImage);
                  }
              }
          }
          for (Entry<ConfigResource, ConfigurationDelta> entry : changes.entrySet()) {
              if (!newData.containsKey(entry.getKey())) {
                  ConfigurationImage newImage = entry.getValue().apply();
                  if (!newImage.isEmpty()) {
                      newData.put(entry.getKey(), newImage);
                  }
              }
          }
          return new ConfigurationsImage(newData);
      }
  
      @Override
      public String toString() {
          return "ConfigurationsDelta(" +
              "changes=" + changes +
              ')';
      }
  }
  