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.segment;
  
  import java.io.Closeable;
  import java.io.IOException;
  
  import org.apache.cassandra.db.PartitionPosition;
  import org.apache.cassandra.dht.AbstractBounds;
  import org.apache.cassandra.index.sai.QueryContext;
  import org.apache.cassandra.index.sai.StorageAttachedIndex;
  import org.apache.cassandra.index.sai.disk.PrimaryKeyMap;
  import org.apache.cassandra.index.sai.disk.v1.PerColumnIndexFiles;
  import org.apache.cassandra.index.sai.disk.v1.postings.PostingListRangeIterator;
  import org.apache.cassandra.index.sai.iterators.KeyRangeIterator;
  import org.apache.cassandra.index.sai.plan.Expression;
  import org.apache.cassandra.index.sai.postings.PeekablePostingList;
  import org.apache.cassandra.index.sai.postings.PostingList;
  
  /**
   * Abstract reader for individual segments of an on-disk index.
   * <p>
   * Accepts shared resources (token/offset file readers), and uses them to perform lookups against on-disk data
   * structures.
   */
  public abstract class IndexSegmentSearcher implements SegmentOrdering, Closeable
  {
      final PrimaryKeyMap.Factory primaryKeyMapFactory;
      final PerColumnIndexFiles indexFiles;
      final SegmentMetadata metadata;
      final StorageAttachedIndex index;
  
      IndexSegmentSearcher(PrimaryKeyMap.Factory primaryKeyMapFactory,
                           PerColumnIndexFiles perIndexFiles,
                           SegmentMetadata segmentMetadata,
                           StorageAttachedIndex index)
      {
          this.primaryKeyMapFactory = primaryKeyMapFactory;
          this.indexFiles = perIndexFiles;
          this.metadata = segmentMetadata;
          this.index = index;
      }
  
      public static IndexSegmentSearcher open(PrimaryKeyMap.Factory primaryKeyMapFactory,
                                              PerColumnIndexFiles indexFiles,
                                              SegmentMetadata segmentMetadata,
                                              StorageAttachedIndex index) throws IOException
      {
          if (index.termType().isVector())
              return new VectorIndexSegmentSearcher(primaryKeyMapFactory, indexFiles, segmentMetadata, index);
          else if (index.termType().isLiteral())
              return new LiteralIndexSegmentSearcher(primaryKeyMapFactory, indexFiles, segmentMetadata, index);
          else
              return new NumericIndexSegmentSearcher(primaryKeyMapFactory, indexFiles, segmentMetadata, index);
      }
  
      /**
       * @return memory usage of underlying on-disk data structure
       */
      public abstract long indexFileCacheSize();
  
      /**
       * Search on-disk index synchronously.
       *
       * @param expression to filter on disk index
       * @param queryContext to track per sstable cache and per query metrics
       *
       * @return {@link KeyRangeIterator} with matches for the given expression
       */
      public abstract KeyRangeIterator search(Expression expression, AbstractBounds<PartitionPosition> keyRange, QueryContext queryContext) throws IOException;
  
      KeyRangeIterator toPrimaryKeyIterator(PostingList postingList, QueryContext queryContext) throws IOException
      {
          if (postingList == null || postingList.size() == 0)
              return KeyRangeIterator.empty();
  
          IndexSegmentSearcherContext searcherContext = new IndexSegmentSearcherContext(metadata.minKey,
                                                                                        metadata.maxKey,
                                                                                        metadata.rowIdOffset,
                                                                                        queryContext,
                                                                                        PeekablePostingList.makePeekable(postingList));
  
          return new PostingListRangeIterator(index.identifier(), primaryKeyMapFactory.newPerSSTablePrimaryKeyMap(), searcherContext);
      }
  }
  