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.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 CLUSTERING_COLUMN column definition.
   *
   * 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 always indexed by this index (or rather, it is indexed if
   * {@code 
   * n >= columnDef.componentIndex, which will always be the case in practice)
   * and it will generate (makeIndexColumnName()) an index entry whose:
   *   - row key will be ck_i (getIndexedValue()) where i == columnDef.componentIndex.
   *   - cell name will
   *       rk ck_0 ... ck_{i-1} ck_{i+1} ck_n
   *     where rk is the row key of the initial cell and i == columnDef.componentIndex.
   * }
   */
  public class ClusteringColumnIndex extends CassandraIndex
  {
      private final boolean enforceStrictLiveness;
  
      public ClusteringColumnIndex(ColumnFamilyStore baseCfs, IndexMetadata indexDef)
      {
          super(baseCfs, indexDef);
          this.enforceStrictLiveness = baseCfs.metadata.get().enforceStrictLiveness();
      }
  
  
      public ByteBuffer getIndexedValue(ByteBuffer partitionKey,
                                        Clustering<?> clustering,
                                        CellPath path, ByteBuffer cellValue)
      {
          return clustering.bufferAt(indexedColumn.position());
      }
  
      public <T> CBuilder buildIndexClusteringPrefix(ByteBuffer partitionKey,
                                                     ClusteringPrefix<T> prefix,
                                                     CellPath path)
      {
          CBuilder builder = CBuilder.create(getIndexComparator());
          builder.add(partitionKey);
          for (int i = 0; i < Math.min(indexedColumn.position(), prefix.size()); i++)
              builder.add(prefix.get(i), prefix.accessor());
          for (int i = indexedColumn.position() + 1; i < prefix.size(); i++)
              builder.add(prefix.get(i), prefix.accessor());
          return builder;
      }
  
      public IndexEntry decodeEntry(DecoratedKey indexedValue,
                                    Row indexEntry)
      {
          int ckCount = baseCfs.metadata().clusteringColumns().size();
  
          Clustering<?> clustering = indexEntry.clustering();
          CBuilder builder = CBuilder.create(baseCfs.getComparator());
          for (int i = 0; i < indexedColumn.position(); i++)
              builder.add(clustering, i + 1);
  
          builder.add(indexedValue.getKey());
  
          for (int i = indexedColumn.position() + 1; i < ckCount; i++)
              builder.add(clustering, i);
  
          return new IndexEntry(indexedValue,
                                clustering,
                                indexEntry.primaryKeyLivenessInfo().timestamp(),
                                clustering.bufferAt(0),
                                builder.build());
      }
  
      public boolean isStale(Row data, ByteBuffer indexValue, long nowInSec)
      {
          return !data.hasLiveData(nowInSec, enforceStrictLiveness);
      }
  }
  