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.sai.memory;
  
  import java.nio.ByteBuffer;
  import java.util.Iterator;
  
  import com.google.common.base.Preconditions;
  
  import com.carrotsearch.hppc.LongArrayList;
  import com.carrotsearch.hppc.cursors.LongCursor;
  import org.apache.cassandra.index.sai.utils.IndexEntry;
  import org.apache.cassandra.index.sai.utils.TermsIterator;
  import org.apache.cassandra.index.sai.postings.PostingList;
  import org.apache.cassandra.utils.Pair;
  import org.apache.cassandra.utils.bytecomparable.ByteComparable;
  
  /**
   * Iterator over a token range bounded segment of a Memtable index. Used to flush Memtable index segments to disk.
   */
  public class MemtableTermsIterator implements TermsIterator
  {
      private final ByteBuffer minTerm;
      private final ByteBuffer maxTerm;
      private final Iterator<Pair<ByteComparable, LongArrayList>> iterator;
  
      private Pair<ByteComparable, LongArrayList> current;
  
      private long maxSSTableRowId = -1;
      private long minSSTableRowId = Long.MAX_VALUE;
  
      public MemtableTermsIterator(ByteBuffer minTerm,
                                   ByteBuffer maxTerm,
                                   Iterator<Pair<ByteComparable, LongArrayList>> iterator)
      {
          Preconditions.checkArgument(iterator != null);
          this.minTerm = minTerm;
          this.maxTerm = maxTerm;
          this.iterator = iterator;
      }
  
      @Override
      public ByteBuffer getMinTerm()
      {
          return minTerm;
      }
  
      @Override
      public ByteBuffer getMaxTerm()
      {
          return maxTerm;
      }
  
      @Override
      public void close() {}
  
      @Override
      public boolean hasNext()
      {
          return iterator.hasNext();
      }
  
      @Override
      public IndexEntry next()
      {
          current = iterator.next();
          return IndexEntry.create(current.left, postings());
      }
  
      public long getMaxSSTableRowId()
      {
          return maxSSTableRowId;
      }
  
      public long getMinSSTableRowId()
      {
          return minSSTableRowId;
      }
  
      private PostingList postings()
      {
          final LongArrayList list = current.right;
  
          assert list.size() > 0;
  
          final long minSegmentRowID = list.get(0);
          final long maxSegmentRowID = list.get(list.size() - 1);
  
          minSSTableRowId = Math.min(minSSTableRowId, minSegmentRowID);
          maxSSTableRowId = Math.max(maxSSTableRowId, maxSegmentRowID);
  
          final Iterator<LongCursor> it = list.iterator();
  
          return new PostingList()
          {
              @Override
              public long nextPosting()
              {
                  if (!it.hasNext())
                  {
                      return END_OF_STREAM;
                  }
  
                  return it.next().value;
              }
  
              @Override
              public long size()
              {
                  return list.size();
              }
  
              @Override
              public long advance(long targetRowID)
              {
                  throw new UnsupportedOperationException();
              }
          };
      }
  }
  