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.clients.producer;
  
  import org.apache.kafka.common.record.RecordBatch;
  
  /**
   * Class containing the state of a transaction after it has been prepared for a two-phase commit.
   * This state includes the producer ID and epoch, which are needed to commit or abort the transaction.
   */
  public class PreparedTxnState {
      private final long producerId;
      private final short epoch;
  
      /**
       * Creates a new empty PreparedTxnState
       */
      public PreparedTxnState() {
          this.producerId = RecordBatch.NO_PRODUCER_ID;
          this.epoch = RecordBatch.NO_PRODUCER_EPOCH;
      }
  
      /**
       * Creates a new PreparedTxnState from a serialized string representation
       *
       * @param serializedState               The serialized string to deserialize.
       * @throws IllegalArgumentException if the serialized string is not in the expected format
       */
      public PreparedTxnState(String serializedState) {
          if (serializedState == null || serializedState.isEmpty()) {
              this.producerId = RecordBatch.NO_PRODUCER_ID;
              this.epoch = RecordBatch.NO_PRODUCER_EPOCH;
              return;
          }
  
          try {
              String[] parts = serializedState.split(":");
              if (parts.length != 2) {
                  throw new IllegalArgumentException("Invalid serialized transaction state format: " + serializedState);
              }
  
              this.producerId = Long.parseLong(parts[0]);
              this.epoch = Short.parseShort(parts[1]);
  
              // Validate the producerId and epoch values.
              if (!(this.producerId >= 0 && this.epoch >= 0)) {
                  throw new IllegalArgumentException("Invalid producer ID and epoch values: " +
                      producerId + ":" + epoch + ". Both must be >= 0");
              }
          } catch (NumberFormatException e) {
              throw new IllegalArgumentException("Invalid serialized transaction state format: " + serializedState, e);
          }
      }
  
      /**
       * Creates a new PreparedTxnState with the given producer ID and epoch
       *
       * @param producerId        The producer ID
       * @param epoch             The producer epoch
       */
      PreparedTxnState(long producerId, short epoch) {
          this.producerId = producerId;
          this.epoch = epoch;
      }
  
      public long producerId() {
          return producerId;
      }
  
      public short epoch() {
          return epoch;
      }
  
      /**
       * Checks if this preparedTxnState represents an initialized transaction with a valid producer ID
       * that is not -1 (the uninitialized value).
       *
       * @return true if the state has an initialized transaction, false otherwise.
       */
      public boolean hasTransaction() {
          return producerId != RecordBatch.NO_PRODUCER_ID;
      }
  
      /**
       * Returns a serialized string representation of this transaction state.
       * The format is "producerId:epoch" for an initialized state, or an empty string
       * for an uninitialized state (where producerId and epoch are both -1).
       *
       * @return a serialized string representation
       */
      @Override
      public String toString() {
          if (!hasTransaction()) {
              return "";
          }
          return producerId + ":" + epoch;
      }
  
      @Override
      public boolean equals(Object o) {
          if (this == o) return true;
          if (o == null || getClass() != o.getClass()) return false;
          PreparedTxnState that = (PreparedTxnState) o;
          return producerId == that.producerId && epoch == that.epoch;
      }
  
      @Override
      public int hashCode() {
          int result = 31;
          result = 31 * result + Long.hashCode(producerId);
          result = 31 * result + (int) epoch;
          return result;
      }
  }
  