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.metadata.ConfigRecord;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.Optional;
  
  
  /**
   * Represents changes to the configurations in the metadata image.
   */
  public final class ConfigurationDelta {
      private final ConfigurationImage image;
      private final Map<String, Optional<String>> changes = new HashMap<>();
  
      public ConfigurationDelta(ConfigurationImage image) {
          this.image = image;
      }
  
      public void finishSnapshot() {
          for (String key : image.data().keySet()) {
              if (!changes.containsKey(key)) {
                  changes.put(key, Optional.empty());
              }
          }
      }
  
      public void replay(ConfigRecord record) {
          changes.put(record.name(), Optional.ofNullable(record.value()));
      }
  
      public void deleteAll() {
          changes.clear();
          for (String key : image.data().keySet()) {
              changes.put(key, Optional.empty());
          }
      }
  
      public ConfigurationImage apply() {
          Map<String, String> newData = new HashMap<>(image.data().size());
          for (Entry<String, String> entry : image.data().entrySet()) {
              Optional<String> change = changes.get(entry.getKey());
              if (change == null) {
                  newData.put(entry.getKey(), entry.getValue());
              } else if (change.isPresent()) {
                  newData.put(entry.getKey(), change.get());
              }
          }
          for (Entry<String, Optional<String>> entry : changes.entrySet()) {
              if (!newData.containsKey(entry.getKey())) {
                  if (entry.getValue().isPresent()) {
                      newData.put(entry.getKey(), entry.getValue().get());
                  }
              }
          }
          return new ConfigurationImage(image.resource(), newData);
      }
  
      @Override
      public String toString() {
          // Values are intentionally left out of this so that sensitive configs
          // do not end up in logging by mistake.
          return "ConfigurationDelta(" +
              "changedKeys=" + changes.keySet() +
              ')';
      }
  }
  