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 * 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
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package org.apache.lucene.spatial.prefix;

import java.util.ArrayList;
import java.util.List;

import org.apache.lucene.search.Query;
import org.apache.lucene.search.TermInSetQuery;
import org.apache.lucene.spatial.prefix.tree.Cell;
import org.apache.lucene.spatial.prefix.tree.CellIterator;
import org.apache.lucene.spatial.prefix.tree.SpatialPrefixTree;
import org.apache.lucene.spatial.query.SpatialArgs;
import org.apache.lucene.spatial.query.SpatialOperation;
import org.apache.lucene.spatial.query.UnsupportedSpatialOperation;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.BytesRefBuilder;
import org.locationtech.spatial4j.shape.Point;
import org.locationtech.spatial4j.shape.Shape;

A basic implementation of PrefixTreeStrategy using a large TermInSetQuery of all the cells from SpatialPrefixTree.getTreeCellIterator(Shape, int). It only supports the search of indexed Point shapes. 

The precision of query shapes (distErrPct) is an important factor in using
this Strategy. If the precision is too precise then it will result in many
terms which will amount to a slower query.
@lucene.experimental
/**
 * A basic implementation of {@link PrefixTreeStrategy} using a large
 * {@link TermInSetQuery} of all the cells from
 * {@link SpatialPrefixTree#getTreeCellIterator(org.locationtech.spatial4j.shape.Shape, int)}.
 * It only supports the search of indexed Point shapes.
 * <p>
 * The precision of query shapes (distErrPct) is an important factor in using
 * this Strategy. If the precision is too precise then it will result in many
 * terms which will amount to a slower query.
 *
 * @lucene.experimental
 */
public class TermQueryPrefixTreeStrategy extends PrefixTreeStrategy {

  protected boolean simplifyIndexedCells = false;

  public TermQueryPrefixTreeStrategy(SpatialPrefixTree grid, String fieldName) {
    super(grid, fieldName);
  }

  @Override
  protected CellToBytesRefIterator newCellToBytesRefIterator() {
    //Ensure we don't have leaves, as this strategy doesn't handle them.
    return new CellToBytesRefIterator() {
      @Override
      public BytesRef next() {
        if (!cellIter.hasNext()) {
          return null;
        }
        return cellIter.next().getTokenBytesNoLeaf(bytesRef);
      }
    };
  }

  @Override
  public Query makeQuery(SpatialArgs args) {
    final SpatialOperation op = args.getOperation();
    if (op != SpatialOperation.Intersects)
      throw new UnsupportedSpatialOperation(op);

    Shape shape = args.getShape();
    int detailLevel = grid.getLevelForDistance(args.resolveDistErr(ctx, distErrPct));

    //--get a List of BytesRef for each term we want (no parents, no leaf bytes))
    final int GUESS_NUM_TERMS;
    if (shape instanceof Point)
      GUESS_NUM_TERMS = detailLevel;//perfect guess
    else
      GUESS_NUM_TERMS = 4096;//should this be a method on SpatialPrefixTree?

    BytesRefBuilder masterBytes = new BytesRefBuilder();//shared byte array for all terms
    List<BytesRef> terms = new ArrayList<>(GUESS_NUM_TERMS);

    CellIterator cells = grid.getTreeCellIterator(shape, detailLevel);
    while (cells.hasNext()) {
      Cell cell = cells.next();
      if (!cell.isLeaf())
        continue;
      BytesRef term = cell.getTokenBytesNoLeaf(null);//null because we want a new BytesRef
      //We copy out the bytes because it may be re-used across the iteration. This also gives us the opportunity
      // to use one contiguous block of memory for the bytes of all terms we need.
      masterBytes.grow(masterBytes.length() + term.length);
      masterBytes.append(term);
      term.bytes = null;//don't need; will reset later
      term.offset = masterBytes.length() - term.length;
      terms.add(term);
    }
    //doing this now because if we did earlier, it's possible the bytes needed to grow()
    for (BytesRef byteRef : terms) {
      byteRef.bytes = masterBytes.bytes();
    }
    //unfortunately TermsQuery will needlessly sort & dedupe
    //TODO an automatonQuery might be faster?
    return new TermInSetQuery(getFieldName(), terms);
  }

}