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.exception.MathIllegalArgumentException;
21 import org.hipparchus.exception.MathIllegalStateException;
22 import org.hipparchus.ode.ODEStateAndDerivative;
23 import org.hipparchus.ode.sampling.ODEStateInterpolator;
24
25 /** This interface handles the state for either one {@link ODEEventHandler
26 * event handler} or one {@link ODEStepEndHandler step end handler}
27 * during integration steps.
28 * @since 3.0
29 */
30 public interface EventState {
31
32 /** Initialize handler at the start of an integration.
33 * <p>
34 * This method is called once at the start of the integration. It
35 * may be used by the handler to initialize some internal data
36 * if needed.
37 * </p>
38 * @param s0 initial state
39 * @param t target time for the integration
40 *
41 */
42 void init(ODEStateAndDerivative s0, double t);
43
44 /**
45 * Get the occurrence time of the event triggered in the current step.
46 *
47 * @return occurrence time of the event triggered in the current step or infinity if
48 * no events are triggered
49 */
50 double getEventTime();
51
52 /**
53 * Evaluate the impact of the proposed step on the handler.
54 *
55 * @param interpolator step interpolator for the proposed step
56 * @return true if the event handler triggers an event before the end of the proposed
57 * step
58 * @throws MathIllegalStateException if the interpolator throws one because the
59 * number of functions evaluations is exceeded
60 * @throws MathIllegalArgumentException if the event cannot be bracketed
61 */
62 boolean evaluateStep(ODEStateInterpolator interpolator)
63 throws MathIllegalArgumentException, MathIllegalStateException;
64
65 /**
66 * Notify the user's listener of the event. The event occurs wholly within this method
67 * call including a call to {@link ODEEventHandler#resetState(ODEEventDetector,
68 * ODEStateAndDerivative)} if necessary.
69 *
70 * @param state the state at the time of the event. This must be at the same time as
71 * the current value of {@link #getEventTime()}.
72 * @return the user's requested action and the new state if the action is {@link
73 * Action#RESET_STATE}. Otherwise the new state is {@code state}. The stop time
74 * indicates what time propagation should stop if the action is {@link Action#STOP}.
75 * This guarantees the integration will stop on or after the root, so that integration
76 * may be restarted safely.
77 */
78 EventOccurrence doEvent(ODEStateAndDerivative state);
79
80 }