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.fqltool.commands;
  
  
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.stream.Collectors;
  
  import com.google.common.annotations.VisibleForTesting;
  import com.google.common.collect.AbstractIterator;
  
  import net.openhft.chronicle.core.io.Closeable;
  import net.openhft.chronicle.queue.ChronicleQueue;
  import net.openhft.chronicle.queue.ExcerptTailer;
  import net.openhft.chronicle.queue.impl.single.SingleChronicleQueueBuilder;
  import org.apache.cassandra.fqltool.FQLQueryIterator;
  import org.apache.cassandra.fqltool.ResultHandler;
  import org.apache.cassandra.fqltool.StoredResultSet;
  import picocli.CommandLine.Command;
  import picocli.CommandLine.Option;
  import picocli.CommandLine.Parameters;
  
  /**
   */
  @Command(name = "compare", description = "Compare result files generated by fqltool replay")
  public class Compare implements Runnable
  {
      @Parameters(paramLabel = "path", description = "Directories containing result files to compare.", arity = "1..*")
      private List<String> arguments = new ArrayList<>();
  
      @Option(paramLabel = "queries",
              names = { "--queries" },
              description = "Directory to read the queries from. It is produced by the fqltool replay --store-queries option. ",
              required = true)
      private String querylog;
  
      @Override
      public void run()
      {
          compare(querylog, arguments);
      }
  
      public static void compare(String querylog, List<String> arguments)
      {
          List<ChronicleQueue> readQueues = null;
          try (ResultHandler rh = new ResultHandler(arguments, null, null);
               ChronicleQueue queryQ = SingleChronicleQueueBuilder.single(querylog).readOnly(true).build();
               FQLQueryIterator queries = new FQLQueryIterator(queryQ.createTailer(), 1))
          {
              readQueues = arguments.stream().map(s -> SingleChronicleQueueBuilder.single(s).readOnly(true).build()).collect(Collectors.toList());
              List<Iterator<ResultHandler.ComparableResultSet>> its = readQueues.stream().map(q -> new StoredResultSetIterator(q.createTailer())).collect(Collectors.toList());
              while (queries.hasNext())
                  rh.handleResults(queries.next(), resultSets(its));
          }
          catch (Exception e)
          {
              throw new RuntimeException(e);
          }
          finally
          {
              if (readQueues != null)
                  readQueues.forEach(Closeable::close);
          }
      }
  
      @VisibleForTesting
      public static List<ResultHandler.ComparableResultSet> resultSets(List<Iterator<ResultHandler.ComparableResultSet>> its)
      {
          List<ResultHandler.ComparableResultSet> resultSets = new ArrayList<>(its.size());
          for (Iterator<ResultHandler.ComparableResultSet> it : its)
          {
              if (it.hasNext())
                  resultSets.add(it.next());
              else
                  resultSets.add(null);
          }
          return resultSets;
      }
  
      @VisibleForTesting
      public static class StoredResultSetIterator extends AbstractIterator<ResultHandler.ComparableResultSet>
      {
          private final ExcerptTailer tailer;
  
          public StoredResultSetIterator(ExcerptTailer tailer)
          {
              this.tailer = tailer;
          }
  
          protected ResultHandler.ComparableResultSet computeNext()
          {
              StoredResultSet srs = StoredResultSet.fromTailer(tailer);
              if (srs.hasMoreResultSets)
                  return srs;
              return endOfData();
          }
      }
  
  
  }
  