1 /*
2 * Licensed to the Hipparchus project under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The Hipparchus project 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 * https://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.hipparchus.ode.events;
19
20 import org.hipparchus.ode.ODEState;
21 import org.hipparchus.ode.ODEStateAndDerivative;
22 import org.hipparchus.ode.sampling.ODEStateInterpolator;
23
24 /** This class handles the state for one {@link ODEEventHandler
25 * event handler} that triggers at step end.
26 * @since 3.0
27 */
28 public class StepEndEventState implements EventState {
29
30 /** Step end handler. */
31 private final ODEStepEndHandler handler;
32
33 /** Time at step end. */
34 private double stepEnd;
35
36 /** Integration direction. */
37 private boolean forward;
38
39 /** Simple constructor.
40 * @param handler step end handler
41 */
42 public StepEndEventState(final ODEStepEndHandler handler) {
43 this.handler = handler;
44 this.stepEnd = Double.NaN;
45 }
46
47 /** Get the underlying step end handler.
48 * @return underlying step end handler
49 */
50 public ODEStepEndHandler getHandler() {
51 return handler;
52 }
53
54 /** {@inheritDoc} */
55 @Override
56 public void init(final ODEStateAndDerivative s0, final double t) {
57 forward = t >= s0.getTime();
58 }
59
60 /** Set the step end.
61 * @param stepEnd step end
62 */
63 public void setStepEnd(final double stepEnd) {
64 this.stepEnd = stepEnd;
65 }
66
67 /** {@inheritDoc} */
68 @Override
69 public boolean evaluateStep(final ODEStateInterpolator interpolator) {
70 return stepEnd == interpolator.getCurrentState().getTime();
71 }
72
73 /** {@inheritDoc} */
74 @Override
75 public double getEventTime() {
76 return stepEnd;
77 }
78
79 /** {@inheritDoc} */
80 @Override
81 public EventOccurrence doEvent(final ODEStateAndDerivative state) {
82
83 final Action action = handler.stepEndOccurred(state, forward);
84 final ODEState newState;
85 if (action == Action.RESET_STATE) {
86 newState = handler.resetState(state);
87 } else {
88 newState = state;
89 }
90
91 final EventOccurrence occurrence = new EventOccurrence(action, newState, stepEnd);
92 setStepEnd(Double.NaN);
93 return occurrence;
94
95 }
96
97 }