EventsLogger.java
/* Copyright 2002-2022 CS GROUP
* Licensed to CS GROUP (CS) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.orekit.propagation.events;
import java.util.ArrayList;
import java.util.List;
import org.hipparchus.ode.events.Action;
import org.orekit.propagation.SpacecraftState;
import org.orekit.propagation.events.handlers.EventHandler;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.TimeStamped;
/** This class logs events detectors events during propagation.
*
* <p>As {@link EventDetector events detectors} are triggered during
* orbit propagation, an event specific {@link
* EventDetector#eventOccurred(SpacecraftState, boolean) eventOccurred}
* method is called. This class can be used to add a global logging
* feature registering all events with their corresponding states in
* a chronological sequence (or reverse-chronological if propagation
* occurs backward).
* <p>This class works by wrapping user-provided {@link EventDetector
* events detectors} before they are registered to the propagator. The
* wrapper monitor the calls to {@link
* EventDetector#eventOccurred(SpacecraftState, boolean) eventOccurred}
* and store the corresponding events as {@link LoggedEvent} instances.
* After propagation is complete, the user can retrieve all the events
* that have occurred at once by calling method {@link #getLoggedEvents()}.</p>
*
* @author Luc Maisonobe
*/
public class EventsLogger {
/** List of occurred events. */
private final List<LoggedEvent> log;
/** Simple constructor.
* <p>
* Build an empty logger for events detectors.
* </p>
*/
public EventsLogger() {
log = new ArrayList<EventsLogger.LoggedEvent>();
}
/** Monitor an event detector.
* <p>
* In order to monitor an event detector, it must be wrapped thanks to
* this method as follows:
* </p>
* <pre>
* Propagator propagator = new XyzPropagator(...);
* EventsLogger logger = new EventsLogger();
* EventDetector detector = new UvwDetector(...);
* propagator.addEventDetector(logger.monitorDetector(detector));
* </pre>
* <p>
* Note that the event detector returned by the {@link
* LoggedEvent#getEventDetector() getEventDetector} method in
* {@link LoggedEvent LoggedEvent} instances returned by {@link
* #getLoggedEvents()} are the {@code monitoredDetector} instances
* themselves, not the wrapping detector returned by this method.
* </p>
* @param monitoredDetector event detector to monitor
* @return the wrapping detector to add to the propagator
* @param <T> class type for the generic version
*/
public <T extends EventDetector> EventDetector monitorDetector(final T monitoredDetector) {
return new LoggingWrapper<T>(monitoredDetector);
}
/** Clear the logged events.
*/
public void clearLoggedEvents() {
log.clear();
}
/** Get an immutable copy of the logged events.
* <p>
* The copy is independent of the logger. It is preserved
* event if the {@link #clearLoggedEvents() clearLoggedEvents} method
* is called and the logger reused in another propagation.
* </p>
* @return an immutable copy of the logged events
*/
public List<LoggedEvent> getLoggedEvents() {
return new ArrayList<EventsLogger.LoggedEvent>(log);
}
/** Class for logged events entries. */
public static class LoggedEvent implements TimeStamped {
/** Event detector triggered. */
private final EventDetector detector;
/** Triggering state. */
private final SpacecraftState state;
/** Increasing/decreasing status. */
private final boolean increasing;
/** Simple constructor.
* @param detector detector for event that was triggered
* @param state state at event trigger date
* @param increasing indicator if the event switching function was increasing
* or decreasing at event occurrence date
*/
private LoggedEvent(final EventDetector detector, final SpacecraftState state, final boolean increasing) {
this.detector = detector;
this.state = state;
this.increasing = increasing;
}
/** Get the event detector triggered.
* @return event detector triggered
*/
public EventDetector getEventDetector() {
return detector;
}
/** {@inheritDoc} */
@Override
public AbsoluteDate getDate() {
return state.getDate();
}
/** Get the triggering state.
* @return triggering state
* @see EventDetector#eventOccurred(SpacecraftState, boolean)
*/
public SpacecraftState getState() {
return state;
}
/** Get the Increasing/decreasing status of the event.
* @return increasing/decreasing status of the event
* @see EventDetector#eventOccurred(SpacecraftState, boolean)
*/
public boolean isIncreasing() {
return increasing;
}
}
/** Internal wrapper for events detectors.
* @param <T> class type for the generic version
*/
private class LoggingWrapper<T extends EventDetector> extends AbstractDetector<LoggingWrapper<T>> {
/** Wrapped events detector. */
private final T detector;
/** Simple constructor.
* @param detector events detector to wrap
*/
LoggingWrapper(final T detector) {
this(detector.getMaxCheckInterval(), detector.getThreshold(),
detector.getMaxIterationCount(), new LocalHandler<T>(),
detector);
}
/** Private constructor with full parameters.
* <p>
* This constructor is private as users are expected to use the builder
* API with the various {@code withXxx()} methods to set up the instance
* in a readable manner without using a huge amount of parameters.
* </p>
* @param maxCheck maximum checking interval (s)
* @param threshold convergence threshold (s)
* @param maxIter maximum number of iterations in the event time search
* @param handler event handler to call at event occurrences
* @param detector events detector to wrap
* @since 6.1
*/
private LoggingWrapper(final double maxCheck, final double threshold,
final int maxIter, final EventHandler<? super LoggingWrapper<T>> handler,
final T detector) {
super(maxCheck, threshold, maxIter, handler);
this.detector = detector;
}
/** {@inheritDoc} */
@Override
protected LoggingWrapper<T> create(final double newMaxCheck, final double newThreshold,
final int newMaxIter, final EventHandler<? super LoggingWrapper<T>> newHandler) {
return new LoggingWrapper<T>(newMaxCheck, newThreshold, newMaxIter, newHandler, detector);
}
/** Log an event.
* @param state state at event trigger date
* @param increasing indicator if the event switching function was increasing
*/
public void logEvent(final SpacecraftState state, final boolean increasing) {
log.add(new LoggedEvent(detector, state, increasing));
}
/** {@inheritDoc} */
public void init(final SpacecraftState s0,
final AbsoluteDate t) {
super.init(s0, t);
detector.init(s0, t);
}
/** {@inheritDoc} */
public double g(final SpacecraftState s) {
return detector.g(s);
}
}
/** Local class for handling events.
* @param <T> class type for the generic version
*/
private static class LocalHandler<T extends EventDetector> implements EventHandler<LoggingWrapper<T>> {
/** {@inheritDoc} */
public Action eventOccurred(final SpacecraftState s, final LoggingWrapper<T> wrapper, final boolean increasing) {
wrapper.logEvent(s, increasing);
return wrapper.detector.eventOccurred(s, increasing);
}
/** {@inheritDoc} */
@Override
public SpacecraftState resetState(final LoggingWrapper<T> wrapper, final SpacecraftState oldState) {
return wrapper.detector.resetState(oldState);
}
}
}