1   /* Copyright 2022-2025 Luc Maisonobe
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.time;
18  
19  import org.hipparchus.CalculusFieldElement;
20  
21  /** Base class for time scales with constant offset with respect to to TAI.
22   * @author Luc Maisonobe
23   * @since 12.1
24   */
25  public class ConstantOffsetTimeScale implements TimeScale {
26  
27      /** Name of the time scale. */
28      private final String name;
29  
30      /** Offset from TAI. */
31      private final TimeOffset offset;
32  
33      /** Negated offset from TAI.
34       * @since 13.0
35       */
36      private final TimeOffset negatedOffset;
37  
38      /** Simple constructor.
39       * @param name name of the time scale
40       * @param offset offset from TAI
41       */
42      public ConstantOffsetTimeScale(final String name, final TimeOffset offset) {
43          this.name          = name;
44          this.offset        = offset;
45          this.negatedOffset = offset.negate();
46      }
47  
48      /** {@inheritDoc} */
49      @Override
50      public TimeOffset offsetFromTAI(final AbsoluteDate date) {
51          return offset;
52      }
53  
54      /** {@inheritDoc} */
55      @Override
56      public <T extends CalculusFieldElement<T>> T offsetFromTAI(final FieldAbsoluteDate<T> date) {
57          return date.getField().getZero().newInstance(offset.toDouble());
58      }
59  
60      /** {@inheritDoc} */
61      @Override
62      public TimeOffset offsetToTAI(final DateComponents date, final TimeComponents time) {
63          return negatedOffset;
64      }
65  
66      /** {@inheritDoc} */
67      public String getName() {
68          return name;
69      }
70  
71      /** {@inheritDoc} */
72      public String toString() {
73          return getName();
74      }
75  
76  }