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.index.sai.disk.v1;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.function.IntSupplier;
  import java.util.function.Supplier;
  import java.util.stream.IntStream;
  import java.util.stream.Stream;
  
  import com.carrotsearch.hppc.LongArrayList;
  import org.apache.cassandra.utils.Pair;
  import org.apache.cassandra.utils.bytecomparable.ByteComparable;
  
  import static java.util.stream.Collectors.toList;
  
  public class InvertedIndexBuilder
  {
      public static List<Pair<ByteComparable, LongArrayList>> buildStringTermsEnum(int terms, int postings, Supplier<String> termsGenerator, IntSupplier postingsGenerator)
      {
          final List<ByteComparable> sortedTerms = Stream.generate(termsGenerator)
                                                         .distinct()
                                                         .limit(terms)
                                                         .sorted()
                                                         .map(ByteComparable::of)
                                                         .collect(toList());
  
          final List<Pair<ByteComparable, LongArrayList>> termsEnum = new ArrayList<>();
          for (ByteComparable term : sortedTerms)
          {
              final LongArrayList postingsList = new LongArrayList();
  
              IntStream.generate(postingsGenerator)
                       .distinct()
                       .limit(postings)
                       .sorted()
                       .forEach(postingsList::add);
  
              termsEnum.add(Pair.create(term, postingsList));
          }
          return termsEnum;
      }
  }
  