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.io.sstable;
  
  import java.io.IOException;
  import java.util.concurrent.locks.ReadWriteLock;
  
  import org.apache.cassandra.db.DecoratedKey;
  import org.apache.cassandra.db.PartitionPosition;
  import org.apache.cassandra.dht.AbstractBounds;
  import org.apache.cassandra.dht.IPartitioner;
  import org.apache.cassandra.utils.AbstractIterator;
  import org.apache.cassandra.utils.CloseableIterator;
  
  public class KeyIterator extends AbstractIterator<DecoratedKey> implements CloseableIterator<DecoratedKey>
  {
      private final AbstractBounds<PartitionPosition> bounds;
      private final IPartitioner partitioner;
      private final KeyReader it;
      private final ReadWriteLock fileAccessLock;
      private final long totalBytes;
  
      private boolean initialized = false;
  
      public KeyIterator(AbstractBounds<PartitionPosition> bounds, KeyReader it, IPartitioner partitioner, long totalBytes, ReadWriteLock fileAccessLock)
      {
          this.bounds = bounds;
          this.it = it;
          this.partitioner = partitioner;
          this.totalBytes = totalBytes;
          this.fileAccessLock = fileAccessLock;
      }
  
      protected DecoratedKey computeNext()
      {
          if (fileAccessLock != null)
              fileAccessLock.readLock().lock();
          try
          {
              while (true)
              {
                  if (!initialized)
                  {
                      initialized = true;
                      if (it.isExhausted())
                          break;
                  }
                  else if (!it.advance())
                      break;
  
                  DecoratedKey key = partitioner.decorateKey(it.key());
                  if (bounds == null || bounds.contains(key))
                      return key;
  
                  if (key.compareTo(bounds.right) >= 0)
                      break;
              }
  
              return endOfData();
          }
          catch (IOException e)
          {
              throw new RuntimeException(e);
          }
          finally
          {
              if (fileAccessLock != null)
                  fileAccessLock.readLock().unlock();
          }
      }
  
      public void close()
      {
          if (fileAccessLock != null)
              fileAccessLock.writeLock().lock();
          try
          {
              it.close();
          }
          finally
          {
              if (fileAccessLock != null)
                  fileAccessLock.writeLock().unlock();
          }
      }
  
      public long getBytesRead()
      {
          if (fileAccessLock != null)
              fileAccessLock.readLock().lock();
          try
          {
              return it.isExhausted() ? totalBytes : it.dataPosition();
          }
          finally
          {
              if (fileAccessLock != null)
                  fileAccessLock.readLock().unlock();
          }
      }
  
      public long getTotalBytes()
      {
          return totalBytes;
      }
  
  }
  