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.service.reads.range;
  
  import org.apache.cassandra.db.partitions.PartitionIterator;
  import org.apache.cassandra.db.rows.RowIterator;
  import org.apache.cassandra.exceptions.ReadTimeoutException;
  import org.apache.cassandra.locator.EndpointsForRange;
  import org.apache.cassandra.locator.ReplicaPlan;
  import org.apache.cassandra.locator.ReplicaPlan.ForRangeRead;
  import org.apache.cassandra.service.reads.DataResolver;
  import org.apache.cassandra.service.reads.ReadCallback;
  import org.apache.cassandra.service.reads.repair.ReadRepair;
  import org.apache.cassandra.utils.AbstractIterator;
  
  class SingleRangeResponse extends AbstractIterator<RowIterator> implements PartitionIterator
  {
      private final DataResolver<EndpointsForRange, ReplicaPlan.ForRangeRead> resolver;
      private final ReadCallback<EndpointsForRange, ReplicaPlan.ForRangeRead> handler;
      private final ReadRepair<EndpointsForRange, ReplicaPlan.ForRangeRead> readRepair;
  
      private PartitionIterator result;
  
      SingleRangeResponse(DataResolver<EndpointsForRange, ReplicaPlan.ForRangeRead> resolver,
                          ReadCallback<EndpointsForRange, ReplicaPlan.ForRangeRead> handler,
                          ReadRepair<EndpointsForRange, ReplicaPlan.ForRangeRead> readRepair)
      {
          this.resolver = resolver;
          this.handler = handler;
          this.readRepair = readRepair;
      }
  
      public ReadRepair<EndpointsForRange, ForRangeRead> getReadRepair()
      {
          return readRepair;
      }
  
      private void waitForResponse() throws ReadTimeoutException
      {
          if (result != null)
              return;
  
          handler.awaitResults();
          result = resolver.resolve();
      }
  
      @Override
      protected RowIterator computeNext()
      {
          waitForResponse();
          return result.hasNext() ? result.next() : endOfData();
      }
  
      @Override
      public void close()
      {
          if (result != null)
              result.close();
      }
  }
  