1   /* Copyright 2002-2022 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.files.ccsds.ndm;
18  
19  import org.hipparchus.util.Precision;
20  import org.orekit.errors.OrekitException;
21  import org.orekit.errors.OrekitMessages;
22  import org.orekit.utils.units.Unit;
23  
24  /** Behavior adopted for units that have been parsed from a CCSDS message.
25   * @author Luc Maisonobe
26   * @since 11.0
27   */
28  public enum ParsedUnitsBehavior {
29  
30      /** Ignore parsed units, just relying on CCSDS standard.
31       * <p>
32       * When this behavior is selected having a unit parsed as second
33       * when CCSDS mandates kilometer will be accepted.
34       * </p>
35       */
36      IGNORE_PARSED {
37          /** {@inheritDoc} */
38          @Override
39          public Unit select(final Unit message, final Unit standard) {
40              return standard;
41          }
42      },
43  
44      /** Allow compatible units, performing conversion.
45       * <p>
46       * When this behavior is selected having a unit parsed as second
47       * when CCSDS mandates kilometer will be refused, but having a unit
48       * parsed as meter will be accepted, with proper conversion performed.
49       * Missing units (i.e. units parsed as {@link Unit#NONE}) are considered
50       * to be standard.
51       * </p>
52       */
53      CONVERT_COMPATIBLE {
54          /** {@inheritDoc} */
55          @Override
56          public Unit select(final Unit message, final Unit standard) {
57              if (message == Unit.NONE) {
58                  return standard;
59              } else if (message.sameDimension(standard)) {
60                  return message;
61              } else {
62                  throw new OrekitException(OrekitMessages.INCOMPATIBLE_UNITS,
63                                            message.getName(), standard.getName());
64              }
65          }
66      },
67  
68      /** Enforce strict compliance with CCSDS standard.
69       * <p>
70       * When this behavior is selected having a unit parsed as second
71       * or as meter when CCSDS mandates kilometer will both be refused.
72       * Missing units (i.e. units parsed as {@link Unit#NONE}) are considered
73       * to be standard.
74       * </p>
75       */
76      STRICT_COMPLIANCE {
77          /** {@inheritDoc} */
78          @Override
79          public Unit select(final Unit message, final Unit standard) {
80              if (message == Unit.NONE ||
81                  Precision.equals(message.getScale(), standard.getScale(), 1) &&
82                  message.sameDimension(standard)) {
83                  return standard;
84              } else {
85                  throw new OrekitException(OrekitMessages.INCOMPATIBLE_UNITS,
86                                            message.getName(), standard.getName());
87              }
88          }
89      };
90  
91      /** Select the unit to use for interpreting parsed value.
92       * @param message unit parsed in the CCSDS message
93       * @param standard unit mandated by the standard
94       * @return selected unit
95       */
96      public abstract Unit select(Unit message, Unit standard);
97  
98  }