org.hipparchus.util.IterationManager Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.hipparchus.util;
import java.util.Collection;
import java.util.concurrent.CopyOnWriteArrayList;
import org.hipparchus.exception.MathIllegalStateException;
/**
* This abstract class provides a general framework for managing iterative
* algorithms. The maximum number of iterations can be set, and methods are
* provided to monitor the current iteration count. A lightweight event
* framework is also provided.
*/
public class IterationManager {
/** Keeps a count of the number of iterations. */
private final Incrementor iterations;
/** The collection of all listeners attached to this iterative algorithm. */
private final Collection listeners;
/**
* Creates a new instance of this class.
*
* @param maxIterations the maximum number of iterations
*/
public IterationManager(final int maxIterations) {
this.iterations = new Incrementor(maxIterations);
this.listeners = new CopyOnWriteArrayList();
}
/**
* Creates a new instance of this class.
*
* @param maxIterations the maximum number of iterations
* @param callBack the function to be called when the maximum number of
* iterations has been reached
* @throws org.hipparchus.exception.NullArgumentException if {@code callBack} is {@code null}
*/
public IterationManager(final int maxIterations,
final Incrementor.MaxCountExceededCallback callBack) {
this.iterations = new Incrementor(maxIterations, callBack);
this.listeners = new CopyOnWriteArrayList();
}
/**
* Attaches a listener to this manager.
*
* @param listener A {@code IterationListener} object.
*/
public void addIterationListener(final IterationListener listener) {
listeners.add(listener);
}
/**
* Informs all registered listeners that the initial phase (prior to the
* main iteration loop) has been completed.
*
* @param e The {@link IterationEvent} object.
*/
public void fireInitializationEvent(final IterationEvent e) {
for (IterationListener l : listeners) {
l.initializationPerformed(e);
}
}
/**
* Informs all registered listeners that a new iteration (in the main
* iteration loop) has been performed.
*
* @param e The {@link IterationEvent} object.
*/
public void fireIterationPerformedEvent(final IterationEvent e) {
for (IterationListener l : listeners) {
l.iterationPerformed(e);
}
}
/**
* Informs all registered listeners that a new iteration (in the main
* iteration loop) has been started.
*
* @param e The {@link IterationEvent} object.
*/
public void fireIterationStartedEvent(final IterationEvent e) {
for (IterationListener l : listeners) {
l.iterationStarted(e);
}
}
/**
* Informs all registered listeners that the final phase (post-iterations)
* has been completed.
*
* @param e The {@link IterationEvent} object.
*/
public void fireTerminationEvent(final IterationEvent e) {
for (IterationListener l : listeners) {
l.terminationPerformed(e);
}
}
/**
* Returns the number of iterations of this solver, 0 if no iterations has
* been performed yet.
*
* @return the number of iterations.
*/
public int getIterations() {
return iterations.getCount();
}
/**
* Returns the maximum number of iterations.
*
* @return the maximum number of iterations.
*/
public int getMaxIterations() {
return iterations.getMaximalCount();
}
/**
* Increments the iteration count by one, and throws an exception if the
* maximum number of iterations is reached. This method should be called at
* the beginning of a new iteration.
*
* @throws MathIllegalStateException if the maximum number of iterations is
* reached.
*/
public void incrementIterationCount()
throws MathIllegalStateException {
iterations.increment();
}
/**
* Removes the specified iteration listener from the list of listeners
* currently attached to {@code this} object. Attempting to remove a
* listener which was not previously registered does not cause any
* error.
*
* @param listener The {@link IterationListener} to be removed.
*/
public void removeIterationListener(final IterationListener listener) {
listeners.remove(listener);
}
/**
* Sets the iteration count to 0. This method must be called during the
* initial phase.
*/
public void resetIterationCount() {
iterations.reset();
}
}