src/Lucene.Net.Spatial/Prefix/TermQueryPrefixTreeStrategy.cs

using Lucene.Net.Queries;
using Lucene.Net.Search;
using Lucene.Net.Spatial.Prefix.Tree;
using Lucene.Net.Spatial.Queries;
using Lucene.Net.Util;
using Spatial4n.Core.Shapes;
using System.Collections.Generic;

namespace Lucene.Net.Spatial.Prefix
{
    /*
     * 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.
     */

    /// <summary>
    /// A basic implementation of <see cref="PrefixTreeStrategy"/> using a large
    /// <see cref="Lucene.Net.Queries.TermsFilter"/> of all the cells from
    /// <see cref="Lucene.Net.Spatial.Prefix.Tree.SpatialPrefixTree.GetCells(IShape, int, bool, bool)"/>. 
    /// It only supports the search of indexed Point shapes.
    /// <para/>
    /// 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
    /// </summary>
    public class TermQueryPrefixTreeStrategy : PrefixTreeStrategy
    {
        public TermQueryPrefixTreeStrategy(SpatialPrefixTree grid, string fieldName)
            : base(grid, fieldName, false)//do not simplify indexed cells
        {
        }

        public override Filter MakeFilter(SpatialArgs args)
        {
            SpatialOperation op = args.Operation;
            if (op != SpatialOperation.Intersects)
            {
                throw new UnsupportedSpatialOperation(op);
            }
            IShape shape = args.Shape;
            int detailLevel = m_grid.GetLevelForDistance(args.ResolveDistErr(m_ctx, m_distErrPct));
            IList<Cell> cells = m_grid.GetCells(shape, detailLevel, false /*no parents*/, true /*simplify*/);
            var terms = new BytesRef[cells.Count];
            int i = 0;
            foreach (Cell cell in cells)
            {
                terms[i++] = new BytesRef(cell.TokenString);//TODO use cell.getTokenBytes()
            }
            return new TermsFilter(FieldName, terms);
        }
    }
}