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 */
017
018 package org.apache.commons.math.ode.sampling;
019
020
021 /**
022 * This class is a step handler that does nothing.
023
024 * <p>This class is provided as a convenience for users who are only
025 * interested in the final state of an integration and not in the
026 * intermediate steps. Its handleStep method does nothing.</p>
027 *
028 * <p>Since this class has no internal state, it is implemented using
029 * the Singleton design pattern. This means that only one instance is
030 * ever created, which can be retrieved using the getInstance
031 * method. This explains why there is no public constructor.</p>
032 *
033 * @see StepHandler
034 * @version $Revision: 786881 $ $Date: 2009-06-20 14:53:08 -0400 (Sat, 20 Jun 2009) $
035 * @since 1.2
036 */
037
038 public class DummyStepHandler implements StepHandler {
039
040 /** Private constructor.
041 * The constructor is private to prevent users from creating
042 * instances (Singleton design-pattern).
043 */
044 private DummyStepHandler() {
045 }
046
047 /** Get the only instance.
048 * @return the only instance
049 */
050 public static DummyStepHandler getInstance() {
051 return instance;
052 }
053
054 /** Determines whether this handler needs dense output.
055 * Since this handler does nothing, it does not require dense output.
056 * @return always false
057 */
058 public boolean requiresDenseOutput() {
059 return false;
060 }
061
062 /** Reset the step handler.
063 * Initialize the internal data as required before the first step is
064 * handled.
065 */
066 public void reset() {
067 }
068
069 /**
070 * Handle the last accepted step.
071 * This method does nothing in this class.
072 * @param interpolator interpolator for the last accepted step. For
073 * efficiency purposes, the various integrators reuse the same
074 * object on each call, so if the instance wants to keep it across
075 * all calls (for example to provide at the end of the integration a
076 * continuous model valid throughout the integration range), it
077 * should build a local copy using the clone method and store this
078 * copy.
079 * @param isLast true if the step is the last one
080 */
081 public void handleStep(final StepInterpolator interpolator, final boolean isLast) {
082 }
083
084 /** The only instance. */
085 private static final DummyStepHandler instance = new DummyStepHandler();
086
087 }