1   /* Copyright 2022-2025 Luc Maisonobe
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.propagation.events;
18  
19  import org.hipparchus.CalculusFieldElement;
20  import org.orekit.propagation.FieldSpacecraftState;
21  
22  import java.util.Arrays;
23  
24  /** This interface represents an event enabling predicate function.
25   * @param <T> type of the field elements
26   * @author Luc Maisonobe
27   * @since 12.0
28   */
29  public interface FieldEnablingPredicate<T extends CalculusFieldElement<T>> {
30  
31      /** Compute an event enabling function of state.
32       * @param state current state
33       * @param detector underlying detector
34       * @param g value of the underlying detector for the current state
35       * @return true if the event is enabled (i.e. it can be
36       * triggered), false if it should be ignored
37       */
38      boolean eventIsEnabled(FieldSpacecraftState<T> state, FieldEventDetector<T> detector, T g);
39  
40      /**
41       * Method combining predicated based on the OR logic operator.
42       * @param enablingPredicates predicates
43       * @param <T> field type
44       * @return combined predicate
45       * @since 13.1
46       */
47      @SafeVarargs
48      static <T extends CalculusFieldElement<T>> FieldEnablingPredicate<T> orCombine(FieldEnablingPredicate<T>... enablingPredicates) {
49          return (state, detector, g) -> Arrays.stream(enablingPredicates).anyMatch(p -> p.eventIsEnabled(state, detector, g));
50      }
51  
52      /**
53       * Method combining predicated based on the AND logic operator.
54       * @param enablingPredicates predicates
55       * @param <T> field type
56       * @return combined predicate
57       * @since 13.1
58       */
59      @SafeVarargs
60      static <T extends CalculusFieldElement<T>> FieldEnablingPredicate<T> andCombine(FieldEnablingPredicate<T>... enablingPredicates) {
61          return (state, detector, g) -> Arrays.stream(enablingPredicates).allMatch(p -> p.eventIsEnabled(state, detector, g));
62      }
63  }