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.db.transform;
  
  import net.nicoulaj.compilecommand.annotations.DontInline;
  import org.apache.cassandra.db.rows.BaseRowIterator;
  
  // A Transformation that can stop an iterator earlier than its natural exhaustion
  public abstract class StoppingTransformation<I extends BaseRowIterator<?>> extends Transformation<I>
  {
      protected BaseIterator rows;
      protected BaseIterator partitions;
  
      /**
       * If invoked by a subclass, any partitions iterator this transformation has been applied to will terminate
       * after any currently-processing item is returned, as will any row/unfiltered iterator
       */
      @DontInline
      protected void stop()
      {
          if (partitions != null)
          {
              partitions.stop.isSignalled = true;
              partitions.stopChild.isSignalled = true;
          }
  
          stopInPartition();
      }
  
      /**
       * If invoked by a subclass, any rows/unfiltered iterator this transformation has been applied to will terminate
       * after any currently-processing item is returned
       */
      @DontInline
      protected void stopInPartition()
      {
          if (rows != null)
          {
              rows.stop.isSignalled = true;
              rows.stopChild.isSignalled = true;
          }
      }
  
      @Override
      protected void attachTo(BasePartitions partitions)
      {
          assert this.partitions == null;
          this.partitions = partitions;
      }
  
      @Override
      protected void attachTo(BaseRows rows)
      {
          assert this.rows == null;
          this.rows = rows;
      }
  
      @Override
      protected void onClose()
      {
          partitions = null;
      }
  
      @Override
      protected void onPartitionClose()
      {
          rows = null;
      }
  }
  