1   /* Copyright 2002-2016 CS Systèmes d'Information
2    * Licensed to CS Systèmes d'Information (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 java.io.Serializable;
20  
21  /** Interface for time scales.
22   * <p>This is the interface representing all time scales. Time scales are related
23   * to each other by some offsets that may be discontinuous (for example
24   * the {@link UTCScale UTC scale} with respect to the {@link TAIScale
25   * TAI scale}).</p>
26   * @author Luc Maisonobe
27   * @see AbsoluteDate
28   */
29  public interface TimeScale extends Serializable {
30  
31      /** Get the offset to convert locations from {@link TAIScale} to instance.
32       * @param date conversion date
33       * @return offset in seconds to add to a location in <em>{@link TAIScale}
34       * time scale</em> to get a location in <em>instance time scale</em>
35       * @see #offsetToTAI(DateComponents, TimeComponents)
36       */
37      double offsetFromTAI(AbsoluteDate date);
38  
39      /** Get the offset to convert locations from instance to {@link TAIScale}.
40       * @param date date location in the time scale
41       * @param time time location in the time scale
42       * @return offset in seconds to add to a location in <em>instance time scale</em>
43       * to get a location in <em>{@link TAIScale} time scale</em>
44       * @see #offsetFromTAI(AbsoluteDate)
45       */
46      double offsetToTAI(final DateComponents date, final TimeComponents time);
47  
48      /** Get the name time scale.
49       * @return name of the time scale
50       */
51      String getName();
52  
53  }