1 /* Copyright 2013 Applied Defense Solutions, Inc.
2 * Licensed to CS Communication & Systèmes (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.propagation.events.handlers;
18
19 import org.hipparchus.CalculusFieldElement;
20 import org.hipparchus.ode.events.Action;
21 import org.orekit.propagation.FieldSpacecraftState;
22 import org.orekit.propagation.events.EventDetector;
23 import org.orekit.propagation.events.FieldEventDetector;
24 import org.orekit.time.FieldAbsoluteDate;
25
26
27 /**
28 * An interface defining how to override event handling behavior in the standard
29 * propagator eventing classes without requiring subclassing. In cases where
30 * one wishes to use anonymous classes rather than explicit subclassing this
31 * allows for a more direct way to override the behavior. Event classes have to
32 * specifically support this capability.
33 *
34 * @author Hank Grabowski
35 *
36 * @param <KK> object type that the handler is called from
37 * @since 6.1
38 */
39 public interface FieldEventHandler<KK extends FieldEventDetector<T>, T extends CalculusFieldElement<T>> {
40
41 /** Initialize event handler at the start of a propagation.
42 * <p>
43 * This method is called once at the start of the propagation. It
44 * may be used by the event handler to initialize some internal data
45 * if needed.
46 * </p>
47 * <p>
48 * The default implementation does nothing
49 * </p>
50 * @param initialState initial state
51 * @param target target date for the propagation
52 *
53 */
54 default void init(FieldSpacecraftState<T> initialState,
55 FieldAbsoluteDate<T> target) {
56 // nothing by default
57 }
58
59 /**
60 * eventOccurred method mirrors the same interface method as in {@link EventDetector}
61 * and its subclasses, but with an additional parameter that allows the calling
62 * method to pass in an object from the detector which would have potential
63 * additional data to allow the implementing class to determine the correct
64 * return state.
65 *
66 * @param s SpaceCraft state to be used in the evaluation
67 * @param detector object with appropriate type that can be used in determining correct return state
68 * @param increasing with the event occurred in an "increasing" or "decreasing" slope direction
69 * @return the Action that the calling detector should pass back to the evaluation system
70 *
71 */
72 Action eventOccurred(FieldSpacecraftState<T> s, KK detector, boolean increasing);
73
74 /** Reset the state prior to continue propagation.
75 * <p>This method is called after the step handler has returned and
76 * before the next step is started, but only when {@link
77 * #eventOccurred} has itself returned the {@link Action#RESET_STATE}
78 * indicator. It allows the user to reset the state for the next step,
79 * without perturbing the step handler of the finishing step. If the
80 * {@link #eventOccurred} never returns the {@link Action#RESET_STATE}
81 * indicator, this function will never be called, and it is safe to simply return null.</p>
82 * <p>
83 * The default implementation simply return its argument.
84 * </p>
85 * @param detector object with appropriate type that can be used in determining correct return state
86 * @param oldState old state
87 * @return new state
88 */
89 default FieldSpacecraftState<T> resetState(KK detector, FieldSpacecraftState<T> oldState) {
90 return oldState;
91 }
92 }