1   /* Copyright 2002-2026 CS GROUP
2    * Licensed to CS GROUP (CS) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * CS licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *   http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.orekit.estimation.measurements.gnss;
18  
19  import java.io.Serial;
20  import java.io.Serializable;
21  import java.util.Comparator;
22  
23  /** Comparator for {@link IntegerLeastSquareSolution} instance.
24   * @see IntegerLeastSquareSolution
25   * @author Bryan Cazabonne
26   * @since 11.0
27   */
28  public class IntegerLeastSquareComparator implements Comparator<IntegerLeastSquareSolution>, Serializable {
29  
30      /** Serializable UID. */
31      @Serial
32      private static final long serialVersionUID = 20210813;
33  
34      /** Simple constructor.
35       */
36      public IntegerLeastSquareComparator() {
37          // nothing to do
38      }
39  
40      /** {@inheritDoc}
41       * The comparison is based on the squared
42       * distance to the float solution.
43       */
44      @Override
45      public int compare(final IntegerLeastSquareSolution ilss1,
46                         final IntegerLeastSquareSolution ilss2) {
47  
48          if (ilss1 == null) {
49              return ilss2 == null ? 0 : -1;
50          } else if (ilss2 == null) {
51              return 1;
52          }
53  
54          return Double.compare(ilss1.getSquaredDistance(), ilss2.getSquaredDistance());
55      }
56  
57  }