1   /* Copyright 2002-2021 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  
18  package org.orekit.forces.maneuvers.trigger;
19  
20  import java.util.Collections;
21  import java.util.List;
22  import java.util.stream.Stream;
23  
24  import org.hipparchus.Field;
25  import org.hipparchus.CalculusFieldElement;
26  import org.orekit.forces.maneuvers.Maneuver;
27  import org.orekit.propagation.SpacecraftState;
28  import org.orekit.propagation.events.EventDetector;
29  import org.orekit.propagation.events.FieldEventDetector;
30  import org.orekit.time.AbsoluteDate;
31  import org.orekit.time.FieldAbsoluteDate;
32  import org.orekit.utils.ParameterDriver;
33  
34  /** Generic interface for the maneuver triggers used in a {@link Maneuver}.
35   * @author Maxime Journot
36   * @since 10.2
37   */
38  public interface ManeuverTriggers {
39  
40      /** Initialization method.
41       *  Called in when Maneuver.init(...) is called (from ForceModel.init(...)).
42       * @param initialState initial spacecraft state (at the start of propagation).
43       * @param target date of propagation. Not equal to {@code initialState.getDate()}.
44       */
45      default void init(SpacecraftState initialState, AbsoluteDate target) {
46      }
47  
48      /** Get the event detectors associated with the triggers.
49       * @return the event detectors
50       */
51      Stream<EventDetector> getEventsDetectors();
52  
53      /** Get the event detectors associated with the triggers.
54       * @param field field to which the state belongs
55       * @param <T> extends CalculusFieldElement&lt;T&gt;
56       * @return the event detectors
57       */
58      <T extends CalculusFieldElement<T>> Stream<FieldEventDetector<T>> getFieldEventsDetectors(Field<T> field);
59  
60      /** Find out if the maneuver is firing or not.
61       * @param date current date
62       * @param parameters maneuver triggers parameters
63       * @return true if the maneuver is firing, false otherwise
64       */
65      boolean isFiring(AbsoluteDate date, double[] parameters);
66  
67      /** Find out if the maneuver is firing or not.
68       * @param date current date
69       * @param parameters maneuver triggers parameters
70       * @param <T> extends CalculusFieldElement&lt;T&gt;
71       * @return true if the maneuver is firing, false otherwise
72       */
73      <T extends CalculusFieldElement<T>> boolean isFiring(FieldAbsoluteDate<T> date, T[] parameters);
74  
75      /** Get the maneuver triggers parameter drivers.
76       * @return maneuver triggers parameter drivers
77       */
78      default List<ParameterDriver> getParametersDrivers() {
79          return Collections.emptyList();
80      }
81  
82      /** Get the maneuver name.
83       * @return the maneuver name
84       */
85      default String getName() {
86          return "";
87      }
88  }