RecursivePrefixTreeStrategy.cs

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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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using Lucene.Net.Search;
using Lucene.Net.Spatial.Prefix.Tree;
using Lucene.Net.Spatial.Queries;
using Spatial4n.Core.Shapes;

namespace Lucene.Net.Spatial.Prefix
{
    /// <summary>
    /// Based on {@link RecursivePrefixTreeFilter}.
    /// </summary>
    public class RecursivePrefixTreeStrategy : PrefixTreeStrategy
    {
        private int prefixGridScanLevel;

        public RecursivePrefixTreeStrategy(SpatialPrefixTree grid, string fieldName)
            : base(grid, fieldName)
        {
            prefixGridScanLevel = grid.GetMaxLevels() - 4;//TODO this default constant is dependent on the prefix grid size
        }

        public void SetPrefixGridScanLevel(int prefixGridScanLevel)
        {
            //TODO if negative then subtract from maxlevels
            this.prefixGridScanLevel = prefixGridScanLevel;
        }

        public override Filter MakeFilter(SpatialArgs args)
        {
            var op = args.Operation;
            if (op != SpatialOperation.Intersects)
                throw new UnsupportedSpatialOperation(op);

            Shape shape = args.Shape;

            int detailLevel = grid.GetLevelForDistance(args.ResolveDistErr(ctx, distErrPct));

            return new RecursivePrefixTreeFilter(GetFieldName(), grid, shape, prefixGridScanLevel, detailLevel);
        }

        public override string ToString()
        {
            return GetType().Name + "(prefixGridScanLevel:" + prefixGridScanLevel + ",SPG:(" + grid + "))";
        }
    }
}