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.internal.composites;
  
  import java.nio.ByteBuffer;
  
  import org.apache.cassandra.db.*;
  import org.apache.cassandra.db.marshal.AbstractType;
  import org.apache.cassandra.db.marshal.ByteBufferAccessor;
  import org.apache.cassandra.db.rows.Cell;
  import org.apache.cassandra.db.rows.CellPath;
  import org.apache.cassandra.db.rows.Row;
  import org.apache.cassandra.index.internal.CassandraIndex;
  import org.apache.cassandra.index.internal.IndexEntry;
  import org.apache.cassandra.schema.IndexMetadata;
  
  /**
   * Index on a REGULAR column definition on a composite type.
   *
   * A cell indexed by this index will have the general form:
   *   ck_0 ... ck_n c_name : v
   * where ck_i are the cluster keys, c_name the last component of the cell
   * composite name (or second to last if collections are in use, but this
   * has no impact) and v the cell value.
   *
   * Such a cell is indexed if c_name == columnDef.name, and it will generate
   * (makeIndexColumnName()) an index entry whose:
   *   - row key will be the value v (getIndexedValue()).
   *   - cell name will
   *       rk ck_0 ... ck_n
   *     where rk is the row key of the initial cell. I.e. the index entry store
   *     all the information require to locate back the indexed cell.
   */
  public class RegularColumnIndex extends CassandraIndex
  {
      public RegularColumnIndex(ColumnFamilyStore baseCfs, IndexMetadata indexDef)
      {
          super(baseCfs, indexDef);
      }
  
      public ByteBuffer getIndexedValue(ByteBuffer partitionKey,
                                        Clustering<?> clustering,
                                        CellPath path,
                                        ByteBuffer cellValue)
      {
          return cellValue;
      }
  
      public <T> CBuilder buildIndexClusteringPrefix(ByteBuffer partitionKey,
                                                 ClusteringPrefix<T> prefix,
                                                 CellPath path)
      {
          CBuilder builder = CBuilder.create(getIndexComparator());
          builder.add(partitionKey);
          for (int i = 0; i < prefix.size(); i++)
              builder.add(prefix.get(i), prefix.accessor());
  
          // Note: if indexing a static column, prefix will be Clustering.STATIC_CLUSTERING
          // so the Clustering obtained from builder::build will contain a value for only
          // the partition key. At query time though, this is all that's needed as the entire
          // base table partition should be returned for any mathching index entry.
          return builder;
      }
  
      public IndexEntry decodeEntry(DecoratedKey indexedValue, Row indexEntry)
      {
          Clustering<?> clustering = indexEntry.clustering();
  
          Clustering<?> indexedEntryClustering = null;
          if (getIndexedColumn().isStatic())
              indexedEntryClustering = Clustering.STATIC_CLUSTERING;
          else
          {
              ClusteringComparator baseComparator = baseCfs.getComparator();
              CBuilder builder = CBuilder.create(baseComparator);
              for (int i = 0; i < baseComparator.size(); i++)
                  builder.add(clustering, i + 1);
              indexedEntryClustering = builder.build();
          }
  
          return new IndexEntry(indexedValue,
                                clustering,
                                indexEntry.primaryKeyLivenessInfo().timestamp(),
                                clustering.bufferAt(0),
                                indexedEntryClustering);
      }
  
      private static <V> boolean valueIsEqual(AbstractType<?> type, Cell<V> cell, ByteBuffer value)
      {
          return type.compare(cell.value(), cell.accessor(), value, ByteBufferAccessor.instance) == 0;
      }
  
      public boolean isStale(Row data, ByteBuffer indexValue, long nowInSec)
      {
          Cell<?> cell = data.getCell(indexedColumn);
          return cell == null
              || !cell.isLive(nowInSec)
              || !valueIsEqual(indexedColumn.type, cell, indexValue);
      }
  }
  