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.DelegationTokenRecord;
  import org.apache.kafka.common.metadata.RemoveDelegationTokenRecord;
  import org.apache.kafka.metadata.DelegationTokenData;
  import org.apache.kafka.server.common.MetadataVersion;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.Optional;
  
  
  /**
   * Represents changes to delegation tokens in the metadata image.
   */
  public final class DelegationTokenDelta {
      private final DelegationTokenImage image;
  
      // Key is TokenID which is contained in the value TokenInformation
      private final Map<String, Optional<DelegationTokenData>> changes = new HashMap<>();
  
      public DelegationTokenDelta(DelegationTokenImage image) {
          this.image = image;
      }
  
      public void finishSnapshot() {
          for (String tokenId : image.tokens().keySet()) {
              if (!changes.containsKey(tokenId)) {
                  // If the tokenId from the image did not appear in the snapshot, mark it as removed
                  changes.put(tokenId, Optional.empty());
  
              }
          }
      }
  
      public DelegationTokenImage image() {
          return image;
      }
  
      public Map<String, Optional<DelegationTokenData>> changes() {
          return changes;
      }
  
      public void replay(DelegationTokenRecord record) {
          changes.put(record.tokenId(), Optional.of(DelegationTokenData.fromRecord(record)));
      }
  
      public void replay(RemoveDelegationTokenRecord record) {
          changes.put(record.tokenId(), Optional.empty());
      }
  
      public void handleMetadataVersionChange(MetadataVersion changedMetadataVersion) {
          // nothing to do
      }
  
      public DelegationTokenImage apply() {
          Map<String, DelegationTokenData> newTokens = new HashMap<>();
  
          // Add image entries to newTokens if there isn't a change for that entry.
          // A snapshot of the deltas will call finishSnapshot() first which will add a
          // removal change for all entries in the base image which did not have a change record.
          for (Entry<String, DelegationTokenData> entry : image.tokens().entrySet()) {
              Optional<DelegationTokenData> change = changes.get(entry.getKey());
              if (change == null) {
                  newTokens.put(entry.getKey(), entry.getValue());
              } else if (change.isPresent()) {
                  newTokens.put(entry.getKey(), change.get());
              }
          }
  
          // Add changed entries to newTokens that aren't already in newTokens.
          for (Entry<String, Optional<DelegationTokenData>> entry : changes.entrySet()) {
              if (!newTokens.containsKey(entry.getKey())) {
                  if (entry.getValue().isPresent()) {
                      newTokens.put(entry.getKey(), entry.getValue().get());
                  }
              }
          }
          return new DelegationTokenImage(newTokens);
      }
  
      @Override
      public String toString() {
          return "DelegationTokenDelta(" +
              "changes=" + changes +
              ')';
      }
  }
  