processing/src/main/java/org/apache/druid/segment/data/ImmutableRTreeObjectStrategy.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.druid.segment.data;

import com.google.common.collect.Ordering;
import org.apache.druid.collections.bitmap.BitmapFactory;
import org.apache.druid.collections.spatial.ImmutableRTree;
import org.apache.druid.segment.writeout.WriteOutBytes;

import java.io.IOException;
import java.nio.ByteBuffer;

public class ImmutableRTreeObjectStrategy implements ObjectStrategy<ImmutableRTree>
{
  private static Ordering<ImmutableRTree> comparator = new Ordering<ImmutableRTree>()
  {
    @Override
    public int compare(ImmutableRTree tree, ImmutableRTree tree1)
    {
      if (tree.size() == 0 && tree1.size() == 0) {
        return 0;
      }
      if (tree.size() == 0) {
        return -1;
      }
      if (tree1.size() == 0) {
        return 1;
      }
      return tree.compareTo(tree1);
    }
  }.nullsFirst();

  private final BitmapFactory bitmapFactory;

  public ImmutableRTreeObjectStrategy(BitmapFactory bitmapFactory)
  {
    this.bitmapFactory = bitmapFactory;
  }

  @Override
  public Class<ImmutableRTree> getClazz()
  {
    return ImmutableRTree.class;
  }

  @Override
  public ImmutableRTree fromByteBuffer(ByteBuffer buffer, int numBytes)
  {
    // always create the duplicate buffer for creating the objects as original buffer may have mutations somewhere else which can corrupt objects
    ByteBuffer duplicateBuf = buffer.duplicate();
    duplicateBuf.limit(duplicateBuf.position() + numBytes);
    return new ImmutableRTree(duplicateBuf, bitmapFactory);
  }

  @Override
  public byte[] toBytes(ImmutableRTree val)
  {
    return val.toBytes();
  }

  @Override
  public void writeTo(ImmutableRTree val, WriteOutBytes out) throws IOException
  {
    val.writeTo(out);
  }

  @Override
  public int compare(ImmutableRTree o1, ImmutableRTree o2)
  {
    return comparator.compare(o1, o2);
  }
}