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/*
 * Druid - a distributed column store.
 * Copyright (C) 2012, 2013  Metamarkets Group Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package io.druid.server.coordinator;

import io.druid.timeline.DataSegment;

import java.util.List;
import java.util.Random;

public class RandomBalancerStrategy implements BalancerStrategy
{
  private final ReservoirSegmentSampler sampler = new ReservoirSegmentSampler();

  @Override
  public ServerHolder findNewSegmentHomeReplicator(
      DataSegment proposalSegment, List serverHolders
  )
  {
    if (serverHolders.size()==1)
    {
      return null;
    }
    else
    {
      ServerHolder holder = serverHolders.get(new Random().nextInt(serverHolders.size()));
      while (holder.isServingSegment(proposalSegment))
      {
        holder = serverHolders.get(new Random().nextInt(serverHolders.size()));
      }
      return holder;
    }
  }

  @Override
  public ServerHolder findNewSegmentHomeBalancer(
      DataSegment proposalSegment, List serverHolders
  )
  {
    return null;  //To change body of implemented methods use File | Settings | File Templates.
  }

  @Override
  public BalancerSegmentHolder pickSegmentToMove(List serverHolders)
  {
    return sampler.getRandomBalancerSegmentHolder(serverHolders);
  }

  @Override
  public void emitStats(
      String tier, CoordinatorStats stats, List serverHolderList
  )
  {
  }
}