How to use org.h2.mvstore.rtree

public MVRTreeMap(int dimensions, DataType valueType) {
  super(new SpatialDataType(dimensions), valueType);
  this.keyType = (SpatialDataType) getKeyType();
}

@Override
public SpatialKey next() {
  if (!hasNext()) {
    return null;
  }
  SpatialKey c = current;
  fetchNext();
  return c;
}

private SpatialDataType getSpatialDataType() {
  if (spatialType == null) {
    spatialType = new SpatialDataType(2);
  }
  return spatialType;
}

private float getArea(SpatialKey a) {
  if (a.isNull()) {
    return 0;
  }
  float area = 1;
  for (int i = 0; i < dimensions; i++) {
    area *= a.max(i) - a.min(i);
  }
  return area;
}

private Page split(Page p, long writeVersion) {
  return quadraticSplit ?
      splitQuadratic(p, writeVersion) :
      splitLinear(p, writeVersion);
}

  @Override
  protected boolean check(boolean leaf, SpatialKey key,
      SpatialKey test) {
    if (leaf) {
      return keyType.isInside(key, test);
    }
    return keyType.isOverlap(key, test);
  }
};

@Override
@SuppressWarnings("unchecked")
public V put(SpatialKey key, V value) {
  return (V) putOrAdd(key, value, false);
}

/**
 * Create a new map with the given dimensions and value type.
 *
 * @param <V> the value type
 * @param dimensions the number of dimensions
 * @param valueType the value type
 * @return the map
 */
public static <V> MVRTreeMap<V> create(int dimensions, DataType valueType) {
  return new MVRTreeMap<>(dimensions, valueType);
}

  @Override
  protected boolean check(boolean leaf, SpatialKey key,
      SpatialKey test) {
    return keyType.isOverlap(key, test);
  }
};

@Override
public void read(ByteBuffer buff, Object[] obj, int len, boolean key) {
  for (int i = 0; i < len; i++) {
    obj[i] = read(buff);
  }
}

@Override
public void write(WriteBuffer buff, Object[] obj, int len, boolean key) {
  for (int i = 0; i < len; i++) {
    write(buff, obj[i]);
  }
}

@Override
@SuppressWarnings("unchecked")
public V get(Object key) {
  return (V) get(root, key);
}

@Override
public boolean equals(Object other) {
  if (other == this) {
    return true;
  } else if (!(other instanceof SpatialKey)) {
    return false;
  }
  SpatialKey o = (SpatialKey) other;
  if (id != o.id) {
    return false;
  }
  return equalsIgnoringId(o);
}

@Override
public boolean hasNext() {
  if (!initialized) {
    // init
    pos = new CursorPos(root, 0, null);
    fetchNext();
    initialized = true;
  }
  return current != null;
}

@Override
public long getRowCount(Session session) {
  return treeMap.sizeAsLong();
}

@Override
public void truncate(Session session) {
  treeMap.clear();
}

@Override
public int getMemory(Object obj) {
  if (obj instanceof SpatialKey) {
    return getSpatialDataType().getMemory(obj);
  }
  return getMemory((Value) obj);
}

/**
 * Skip over that many entries. This method is relatively fast (for this
 * map implementation) even if many entries need to be skipped.
 *
 * @param n the number of entries to skip
 */
public void skip(long n) {
  while (hasNext() && n-- > 0) {
    fetchNext();
  }
}

/**
 * Add a given key-value pair. The key should not exist (if it exists, the
 * result is undefined).
 *
 * @param key the key
 * @param value the value
 */
public void add(SpatialKey key, V value) {
  putOrAdd(key, value, true);
}

@Override
public long getRowCountApproximation() {
  return treeMap.sizeAsLong();
}