1   /* Copyright 2002-2025 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.forces.maneuvers.trigger;
18  
19  import org.hipparchus.CalculusFieldElement;
20  import org.orekit.propagation.FieldSpacecraftState;
21  import org.orekit.time.FieldAbsoluteDate;
22  
23  /** Resetter for maneuver triggers.
24   * @param <T> type of the field elements
25   * @see AbstractManeuverTriggers
26   * @author Luc Maisonobe
27   * @since 11.1
28   */
29  public interface FieldManeuverTriggersResetter<T extends CalculusFieldElement<T>> {
30  
31      /** Initialization method called at propagation start.
32       * <p>
33       * The default implementation does nothing.
34       * </p>
35       * @param initialState initial spacecraft state (at the start of propagation).
36       * @param target date of propagation. Not equal to {@code initialState.getDate()}.
37       */
38      default void init(FieldSpacecraftState<T> initialState, FieldAbsoluteDate<T> target) {
39          // nothing by default
40      }
41  
42      /** Observe a maneuver trigger.
43       * <p>
44       * The {@code start} parameter corresponds to physical flow of time
45       * from past to future, not to propagation direction which can be backward.
46       * This means that during forward propagations, the first call will have
47       * {@code start} set to {@code true} and the second call will have
48       * {@code start} set to {@code false}, whereas in backward propagation,
49       * the first call will have {@code start} set to {@code false} and the second
50       * call will have {@code start} set to {@code true}.
51       * </p>
52       * @param state spacecraft state at trigger date (before applying the maneuver)
53       * @param start if true, the trigger is the start of the maneuver
54       */
55      void maneuverTriggered(FieldSpacecraftState<T> state, boolean start);
56  
57      /** Reset state as a maneuver triggers.
58       * @param state spacecraft state at trigger date
59       * @return reset state taking into account maneuver start/stop
60       */
61      FieldSpacecraftState<T> resetState(FieldSpacecraftState<T> state);
62  
63  }