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A module that is everything required to understands Druid Segments

There is a newer version: 0.12.3

/*
 * Licensed to Metamarkets Group Inc. (Metamarkets) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. Metamarkets 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 io.druid.query.groupby.orderby;

import com.google.common.collect.MinMaxPriorityQueue;

import java.util.Iterator;

/**
 * Utility class that supports iterating a priority queue in sorted order.
 */
class OrderedPriorityQueueItems implements Iterable
{
  private MinMaxPriorityQueue rows;

  public OrderedPriorityQueueItems(MinMaxPriorityQueue rows)
  {
    this.rows = rows;
  }

  @Override
  public Iterator iterator()
  {
    return new Iterator() {

      @Override
      public boolean hasNext()
      {
        return !rows.isEmpty();
      }

      @Override
      public T next()
      {
        return rows.poll();
      }

      @Override
      public void remove()
      {
        throw new UnsupportedOperationException("Can't remove any item from an intermediary heap for orderBy/limit");
      }
    };
  }
}