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.cassandra.service;
  
  /**
   * Represents where a timestamp is coming from.
   */
  public enum TimestampSource
  {
      unknown, server, using,
      /**
       * When doing a BATCH some mutations use "server" and others use "using".
       */
      mixed;
      
      public static TimestampSource merge(TimestampSource left, TimestampSource right)
      {
          if (left == right) return left;
          switch (left)
          {
              case unknown:
                  return right;
              case server:
                  if (right == TimestampSource.unknown)
                  {
                      return server;
                  }
                  else if (right == TimestampSource.using || right == TimestampSource.mixed)
                  {
                      return mixed;
                  }
                  throw new UnsupportedOperationException(right.name());
              case using:
                  if (right == TimestampSource.unknown)
                  {
                      return using;
                  }
                  else if (right == TimestampSource.server || right == TimestampSource.mixed)
                  {
                      return mixed;
                  }
                  throw new UnsupportedOperationException(right.name());
              case mixed:
                  return left;
              default:
                  throw new UnsupportedOperationException(left.name());
          }
      }
  
      public static class Collector
      {
          boolean hasServerTimestamp = false;
          boolean hasUserTimestamp = false;
  
          public void collect(TimestampSource source)
          {
              switch (source)
              {
                  case unknown:
                  case server:
                      hasServerTimestamp = true;
                      break;
                  case using:
                      hasUserTimestamp = true;
                      break;
                  case mixed:
                      hasServerTimestamp = true;
                      hasUserTimestamp = true;
                      break;
                  default:
                      throw new UnsupportedOperationException(source.name());
              }
          }
  
          public TimestampSource get()
          {
              if (hasServerTimestamp && hasUserTimestamp) return mixed;
              if (hasServerTimestamp) return server;
              if (hasUserTimestamp) return using;
              throw new IllegalStateException(".get() called before .collect()");
          }
      }
  }
  