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.controller;
  
  import org.apache.kafka.common.errors.InvalidReplicaAssignmentException;
  import org.apache.kafka.metadata.PartitionRegistration;
  import org.apache.kafka.metadata.Replicas;
  
  import java.util.List;
  import java.util.Objects;
  
  
  class PartitionReassignmentRevert {
      private final List<Integer> replicas;
      private final List<Integer> isr;
      private final boolean unclean;
  
      PartitionReassignmentRevert(PartitionRegistration registration) {
          // Figure out the replica list and ISR that we will have after reverting the
          // reassignment. In general, we want to take out any replica that the reassignment
          // was adding, but keep the ones the reassignment was removing. (But see the
          // special case below.)
  
          PartitionReassignmentReplicas ongoingReassignment =
              new PartitionReassignmentReplicas(
                  Replicas.toList(registration.removingReplicas),
                  Replicas.toList(registration.addingReplicas),
                  Replicas.toList(registration.replicas)
              );
  
          this.replicas = ongoingReassignment.originalReplicas();
          this.isr = Replicas.toList(registration.isr);
          this.isr.removeAll(ongoingReassignment.adding());
  
          if (isr.isEmpty()) {
              // In the special case that all the replicas that are in the ISR are also
              // contained in addingReplicas, we choose the first remaining replica and add
              // it to the ISR. This is considered an unclean leader election. Therefore,
              // calling code must check that unclean leader election is enabled before
              // accepting the new ISR.
              if (this.replicas.isEmpty()) {
                  // This should not be reachable, since it would require a partition
                  // starting with an empty replica set prior to the reassignment we are
                  // trying to revert.
                  throw new InvalidReplicaAssignmentException("Invalid replica " +
                      "assignment: addingReplicas contains all replicas.");
              }
              isr.add(replicas.get(0));
              this.unclean = true;
          } else {
              this.unclean = false;
          }
      }
  
      List<Integer> replicas() {
          return replicas;
      }
  
      List<Integer> isr() {
          return isr;
      }
  
      boolean unclean() {
          return unclean;
      }
  
      @Override
      public int hashCode() {
          return Objects.hash(replicas, isr, unclean);
      }
  
      @Override
      public boolean equals(Object o) {
          if (!(o instanceof PartitionReassignmentRevert other)) return false;
          return replicas.equals(other.replicas) &&
              isr.equals(other.isr) &&
              unclean == other.unclean;
      }
  
      @Override
      public String toString() {
          return "PartitionReassignmentRevert(" +
              "replicas=" + replicas + ", " +
              "isr=" + isr + ", " +
              "unclean=" + unclean + ")";
      }
  }
  