iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/read/reader/common/DescPriorityMergeReader.java

/*
 * 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.iotdb.db.storageengine.dataregion.read.reader.common;

import org.apache.tsfile.read.reader.IPointReader;

import java.io.IOException;
import java.util.PriorityQueue;

public class DescPriorityMergeReader extends PriorityMergeReader {

  public DescPriorityMergeReader() {
    super.heap =
        new PriorityQueue<>(
            (o1, o2) -> {
              int timeCompare =
                  Long.compare(o2.currPair().getTimestamp(), o1.currPair().getTimestamp());
              return timeCompare != 0 ? timeCompare : o2.getPriority().compareTo(o1.getPriority());
            });
  }

  @Override
  public void addReader(IPointReader reader, MergeReaderPriority priority, long endTime)
      throws IOException {
    if (reader.hasNextTimeValuePair()) {
      heap.add(new Element(reader, reader.nextTimeValuePair(), priority));
      super.currentReadStopTime = Math.min(currentReadStopTime, endTime);
    } else {
      reader.close();
    }
  }
}