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.common.requests;
  
  import org.apache.kafka.common.Uuid;
  
  public class ShareRequestMetadata {
      /**
       * The first epoch. When used in a ShareFetch request, indicates that the client
       * wants to create a session.
       */
      public static final int INITIAL_EPOCH = 0;
  
      /**
       * An invalid epoch. When used in a ShareFetch request, indicates that the client
       * wants to close an existing session.
       */
      public static final int FINAL_EPOCH = -1;
  
      /**
       *
       */
      public boolean isNewSession() {
          return epoch == INITIAL_EPOCH;
      }
  
      /**
       * Returns true if this is a full share fetch request.
       */
      public boolean isFull() {
          return (this.epoch == INITIAL_EPOCH) || (this.epoch == FINAL_EPOCH);
      }
  
      /**
       * Returns the next epoch.
       *
       * @param prevEpoch The previous epoch.
       * @return          The next epoch.
       */
      public static int nextEpoch(int prevEpoch) {
          if (prevEpoch < 0) {
              // The next epoch after FINAL_EPOCH is always FINAL_EPOCH itself.
              return FINAL_EPOCH;
          } else if (prevEpoch == Integer.MAX_VALUE) {
              return 1;
          } else {
              return prevEpoch + 1;
          }
      }
  
      /**
       * The member ID.
       */
      private final Uuid memberId;
  
      /**
       * The share session epoch.
       */
      private final int epoch;
  
      public ShareRequestMetadata(Uuid memberId, int epoch) {
          this.memberId = memberId;
          this.epoch = epoch;
      }
  
      public static ShareRequestMetadata initialEpoch(Uuid memberId) {
          return new ShareRequestMetadata(memberId, INITIAL_EPOCH);
      }
  
      public ShareRequestMetadata nextEpoch() {
          return new ShareRequestMetadata(memberId, nextEpoch(epoch));
      }
  
      public ShareRequestMetadata nextCloseExistingAttemptNew() {
          return new ShareRequestMetadata(memberId, INITIAL_EPOCH);
      }
  
      public ShareRequestMetadata finalEpoch() {
          return new ShareRequestMetadata(memberId, FINAL_EPOCH);
      }
  
      public Uuid memberId() {
          return memberId;
      }
  
      public int epoch() {
          return epoch;
      }
  
      public boolean isFinalEpoch() {
          return epoch == FINAL_EPOCH;
      }
  
      public String toString() {
          StringBuilder bld = new StringBuilder();
          bld.append("(memberId=").append(memberId).append(", ");
          if (epoch == INITIAL_EPOCH) {
              bld.append("epoch=INITIAL)");
          } else if (epoch == FINAL_EPOCH) {
              bld.append("epoch=FINAL)");
          } else {
              bld.append("epoch=").append(epoch).append(")");
          }
          return bld.toString();
      }
  }