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.view;
  
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.Map;
  
  import org.apache.cassandra.index.sai.disk.SSTableIndex;
  import org.apache.cassandra.index.sai.plan.Expression;
  import org.apache.cassandra.index.sai.utils.IndexTermType;
  import org.apache.cassandra.io.sstable.Descriptor;
  import org.apache.cassandra.io.sstable.format.SSTableReader;
  
  /**
   * The View is an immutable, point in time, view of the avalailable {@link SSTableIndex}es for an index.
   * <p>
   * The view maintains a {@link RangeTermTree} for querying the view by value range. This is used by the
   * {@link org.apache.cassandra.index.sai.plan.QueryViewBuilder} to select the set of {@link SSTableIndex}es
   * to perform a query without needing to query indexes that are known not to contain to the requested
   * expression value range.
   */
  public class View implements Iterable<SSTableIndex>
  {
      private final Map<Descriptor, SSTableIndex> view;
  
      private final RangeTermTree rangeTermTree;
  
      public View(IndexTermType indexTermType, Collection<SSTableIndex> indexes)
      {
          this.view = new HashMap<>();
  
          RangeTermTree.Builder rangeTermTreeBuilder = new RangeTermTree.Builder(indexTermType);
  
          for (SSTableIndex sstableIndex : indexes)
          {
              this.view.put(sstableIndex.getSSTable().descriptor, sstableIndex);
              if (!indexTermType.isVector())
                  rangeTermTreeBuilder.add(sstableIndex);
          }
  
          this.rangeTermTree = rangeTermTreeBuilder.build();
      }
  
      /**
       * Search for a list of {@link SSTableIndex}es that contain values within
       * the value range requested in the {@link Expression}
       */
      public Collection<SSTableIndex> match(Expression expression)
      {
          if (expression.getIndexOperator() == Expression.IndexOperator.ANN)
              return getIndexes();
  
          return rangeTermTree.search(expression);
      }
  
      @Override
      public Iterator<SSTableIndex> iterator()
      {
          return view.values().iterator();
      }
  
      public Collection<SSTableIndex> getIndexes()
      {
          return view.values();
      }
  
      public boolean containsSSTable(SSTableReader sstable)
      {
          return view.containsKey(sstable.descriptor);
      }
  
      public int size()
      {
          return view.size();
      }
  
      @Override
      public String toString()
      {
          return String.format("View{view=%s}", view);
      }
  }
  