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.stress.generate;
  
  import java.util.Set;
  import java.util.TreeSet;
  import java.util.concurrent.ConcurrentLinkedQueue;
  
  import com.datastax.driver.core.TokenRange;
  import org.apache.cassandra.stress.settings.StressSettings;
  
  public class TokenRangeIterator
  {
      private final Set<TokenRange> tokenRanges;
      private final ConcurrentLinkedQueue<TokenRange> pendingRanges;
      private final boolean wrap;
  
      public TokenRangeIterator(StressSettings settings, Set<TokenRange> tokenRanges)
      {
          this.tokenRanges = maybeSplitRanges(tokenRanges, settings.tokenRange.splitFactor);
          this.pendingRanges = new ConcurrentLinkedQueue<>(this.tokenRanges);
          this.wrap = settings.tokenRange.wrap;
      }
  
      private static Set<TokenRange> maybeSplitRanges(Set<TokenRange> tokenRanges, int splitFactor)
      {
          if (splitFactor <= 1)
              return tokenRanges;
  
          Set<TokenRange> ret = new TreeSet<>();
          for (TokenRange range : tokenRanges)
              ret.addAll(range.splitEvenly(splitFactor));
  
          return ret;
      }
  
      public void update()
      {
          // we may race and add to the queue twice but no bad consequence so it's fine if that happens
          // as ultimately only the permits determine when to stop if wrap is true
          if (wrap && pendingRanges.isEmpty())
              pendingRanges.addAll(tokenRanges);
      }
  
      public TokenRange next()
      {
          return pendingRanges.poll();
      }
  
      public boolean exhausted()
      {
          return pendingRanges.isEmpty();
      }
  }
  