001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.math4.util;
018
019import java.util.EventListener;
020
021/**
022 * The listener interface for receiving events occurring in an iterative
023 * algorithm.
024 *
025 */
026public interface IterationListener extends EventListener {
027    /**
028     * Invoked after completion of the initial phase of the iterative algorithm
029     * (prior to the main iteration loop).
030     *
031     * @param e The {@link IterationEvent} object.
032     */
033    void initializationPerformed(IterationEvent e);
034
035    /**
036     * Invoked each time an iteration is completed (in the main iteration loop).
037     *
038     * @param e The {@link IterationEvent} object.
039     */
040    void iterationPerformed(IterationEvent e);
041
042    /**
043     * Invoked each time a new iteration is completed (in the main iteration
044     * loop).
045     *
046     * @param e The {@link IterationEvent} object.
047     */
048    void iterationStarted(IterationEvent e);
049
050    /**
051     * Invoked after completion of the operations which occur after breaking out
052     * of the main iteration loop.
053     *
054     * @param e The {@link IterationEvent} object.
055     */
056    void terminationPerformed(IterationEvent e);
057}