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.FieldEventDetector;
23  
24  
25  /** Handle a detection event and choose what to do next.
26   * <p>KKhe implementation behavior is to {@link
27   * Action#CONTINUE continue} propagation when ascending and to
28   * {@link Action#STOP stop} propagation when descending.</p>
29   *
30   * @author Hank Grabowski
31   *
32   * @param <KK> class type for the generic version
33   */
34  public class FieldStopOnDecreasing <KK extends FieldEventDetector<T>, T extends CalculusFieldElement<T>> implements FieldEventHandler<KK, T> {
35  
36  
37      /** Handle a detection event and choose what to do next.
38       * <p>KKhe implementation behavior is to {@link
39       * Action#CONTINUE continue} propagation when ascending and to
40       * {@link Action#STOP stop} propagation when descending.</p>
41       * @param s the current state information : date, kinematics, attitude
42       * @param detector the detector object calling this method (not used in the evaluation)
43       * @param increasing if true, the value of the switching function increases
44       * when times increases around event
45       * @return {@link Action#STOP} or {@link Action#CONTINUE}
46       */
47      @Override
48      public Action eventOccurred(final FieldSpacecraftState<T> s, final KK detector, final boolean increasing) {
49          return increasing ?  Action.CONTINUE : Action.STOP;
50      }
51  
52  }