StepHandlerMultiplexer.java
/* Copyright 2002-2021 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.sampling;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import org.orekit.propagation.SpacecraftState;
import org.orekit.time.AbsoluteDate;
/** This class gathers several {@link OrekitStepHandler} instances into one.
*
* @author Luc Maisonobe
*/
public class StepHandlerMultiplexer implements OrekitStepHandler {
/** Underlying step handlers. */
private final List<OrekitStepHandler> handlers;
/** Target time. */
private AbsoluteDate target;
/** Last known state. */
private SpacecraftState last;
/** Simple constructor.
*/
public StepHandlerMultiplexer() {
handlers = new ArrayList<>();
}
/** Add a handler for variable size step.
* <p>
* If propagation is ongoing (i.e. global {@link #init(SpacecraftState, AbsoluteDate)
* init} already called and global {@link #finish(SpacecraftState) finish} not called
* yet), then the local {@link OrekitStepHandler#init(SpacecraftState, AbsoluteDate)
* OrekitStepHandler.init} method of the added handler will be called with the last
* known state, so the handler starts properly.
* </p>
* @param handler step handler to add
*/
public void add(final OrekitStepHandler handler) {
handlers.add(handler);
if (last != null) {
// propagation is ongoing, we need to call init now for this handler
handler.init(last, target);
}
}
/** Add a handler for fixed size step.
* <p>
* If propagation is ongoing (i.e. global {@link #init(SpacecraftState, AbsoluteDate)
* init} already called and global {@link #finish(SpacecraftState) finish} not called
* yet), then the local {@link OrekitFixedStepHandler#init(SpacecraftState, AbsoluteDate, double)
* OrekitFixedStepHandler.init} method of the added handler will be called with the
* last known state, so the handler starts properly.
* </p>
* @param h fixed stepsize (s)
* @param handler handler called at the end of each finalized step
* @since 11.0
*/
public void add(final double h, final OrekitFixedStepHandler handler) {
final OrekitStepHandler normalized = new OrekitStepNormalizer(h, handler);
handlers.add(normalized);
if (last != null) {
// propagation is ongoing, we need to call init now for this handler
normalized.init(last, target);
}
}
/** Get an unmodifiable view of all handlers.
* <p>
* Note that if {@link OrekitFixedStepHandler fixed step handlers} have
* been {@link #add(double, OrekitFixedStepHandler)}, then they will
* show up wrapped within {@link OrekitStepNormalizer step normalizers}.
* </p>
* @return an unmodifiable view of all handlers
* @since 11.0
*/
public List<OrekitStepHandler> getHandlers() {
return Collections.unmodifiableList(handlers);
}
/** Remove a handler.
* <p>
* If propagation is ongoing (i.e. global {@link #init(SpacecraftState, AbsoluteDate)
* init} already called and global {@link #finish(SpacecraftState) finish} not called
* yet), then the local {@link OrekitStepHandler#finish(SpacecraftState)
* OrekitStepHandler.finish} method of the removed handler will be called with the last
* known state, so the handler stops properly.
* </p>
* @param handler step handler to remove
* @since 11.0
*/
public void remove(final OrekitStepHandler handler) {
final Iterator<OrekitStepHandler> iterator = handlers.iterator();
while (iterator.hasNext()) {
if (iterator.next() == handler) {
if (last != null) {
// propagation is ongoing, we need to call finish now for this handler
handler.finish(last);
}
iterator.remove();
return;
}
}
}
/** Remove a handler.
* <p>
* If propagation is ongoing (i.e. global {@link #init(SpacecraftState, AbsoluteDate)
* init} already called and global {@link #finish(SpacecraftState) finish} not called
* yet), then the local {@link OrekitFixedStepHandler#finish(SpacecraftState)
* OrekitFixedStepHandler.finish} method of the removed handler will be called with the
* last known state, so the handler stops properly.
* </p>
* @param handler step handler to remove
* @since 11.0
*/
public void remove(final OrekitFixedStepHandler handler) {
final Iterator<OrekitStepHandler> iterator = handlers.iterator();
while (iterator.hasNext()) {
final OrekitStepHandler current = iterator.next();
if (current instanceof OrekitStepNormalizer &&
((OrekitStepNormalizer) current).getFixedStepHandler() == handler) {
if (last != null) {
// propagation is ongoing, we need to call finish now for this handler
current.finish(last);
}
iterator.remove();
return;
}
}
}
/** Remove all handlers managed by this multiplexer.
* <p>
* If propagation is ongoing (i.e. global {@link #init(SpacecraftState, AbsoluteDate)
* init} already called and global {@link #finish(SpacecraftState) finish} not called
* yet), then the local {@link OrekitStepHandler#finish(SpacecraftState)
* OrekitStepHandler.finish} and {@link OrekitFixedStepHandler#finish(SpacecraftState)
* OrekitFixedStepHandler.finish} methods of the removed handlers will be called with the
* last known state, so the handlers stop properly.
* </p>
* @since 11.0
*/
public void clear() {
if (last != null) {
// propagation is ongoing, we need to call finish now for all handlers
handlers.forEach(h -> h.finish(last));
}
handlers.clear();
}
/** {@inheritDoc} */
public void init(final SpacecraftState s0, final AbsoluteDate t) {
this.target = t;
this.last = s0;
for (final OrekitStepHandler handler : handlers) {
handler.init(s0, t);
}
}
/** {@inheritDoc} */
public void handleStep(final OrekitStepInterpolator interpolator) {
this.last = interpolator.getCurrentState();
for (final OrekitStepHandler handler : handlers) {
handler.handleStep(interpolator);
}
}
/** {@inheritDoc} */
public void finish(final SpacecraftState finalState) {
this.target = null;
this.last = null;
for (final OrekitStepHandler handler : handlers) {
handler.finish(finalState);
}
}
}