content: /*
   * 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.calcite.runtime;
  
  import org.locationtech.jts.geom.Coordinate;
  import org.locationtech.jts.geom.CoordinateSequence;
  import org.locationtech.jts.geom.Geometry;
  import org.locationtech.jts.geom.impl.CoordinateArraySequence;
  import org.locationtech.jts.geom.util.GeometryTransformer;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * Removes repeated points from a geometry.
   */
  public class RemoveRepeatedPointsTransformer extends GeometryTransformer {
  
    private double tolerance = 0;
  
    public RemoveRepeatedPointsTransformer() {
      super();
    }
  
    public RemoveRepeatedPointsTransformer(double tolerance) {
      super();
      this.tolerance = tolerance;
    }
  
    @Override protected CoordinateSequence transformCoordinates(
        CoordinateSequence coordinates, Geometry parent) {
      List<Coordinate> list = new ArrayList<>();
      Coordinate previous = coordinates.getCoordinate(0);
      list.add(previous);
      for (int i = 1; i < coordinates.size(); i++) {
        Coordinate current = coordinates.getCoordinate(i);
        double distance = current.distance(previous);
        if (distance > tolerance) {
          list.add(current);
          previous = current;
        }
      }
      Coordinate last = coordinates.getCoordinate(coordinates.size() - 1);
      double distance = last.distance(previous);
      if (distance <= tolerance) {
        list.set(list.size() - 1, last);
      }
      Coordinate[] array = list.toArray(new Coordinate[list.size()]);
      return new CoordinateArraySequence(array);
    }
  
  }
  