1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.math.ode.sampling;
19
20
21 /**
22 * This class is a step handler that does nothing.
23
24 * <p>This class is provided as a convenience for users who are only
25 * interested in the final state of an integration and not in the
26 * intermediate steps. Its handleStep method does nothing.</p>
27 *
28 * <p>Since this class has no internal state, it is implemented using
29 * the Singleton design pattern. This means that only one instance is
30 * ever created, which can be retrieved using the getInstance
31 * method. This explains why there is no public constructor.</p>
32 *
33 * @see StepHandler
34 * @version $Revision: 786881 $ $Date: 2009-06-20 14:53:08 -0400 (Sat, 20 Jun 2009) $
35 * @since 1.2
36 */
37
38 public class DummyStepHandler implements StepHandler {
39
40 /** Private constructor.
41 * The constructor is private to prevent users from creating
42 * instances (Singleton design-pattern).
43 */
44 private DummyStepHandler() {
45 }
46
47 /** Get the only instance.
48 * @return the only instance
49 */
50 public static DummyStepHandler getInstance() {
51 return instance;
52 }
53
54 /** Determines whether this handler needs dense output.
55 * Since this handler does nothing, it does not require dense output.
56 * @return always false
57 */
58 public boolean requiresDenseOutput() {
59 return false;
60 }
61
62 /** Reset the step handler.
63 * Initialize the internal data as required before the first step is
64 * handled.
65 */
66 public void reset() {
67 }
68
69 /**
70 * Handle the last accepted step.
71 * This method does nothing in this class.
72 * @param interpolator interpolator for the last accepted step. For
73 * efficiency purposes, the various integrators reuse the same
74 * object on each call, so if the instance wants to keep it across
75 * all calls (for example to provide at the end of the integration a
76 * continuous model valid throughout the integration range), it
77 * should build a local copy using the clone method and store this
78 * copy.
79 * @param isLast true if the step is the last one
80 */
81 public void handleStep(final StepInterpolator interpolator, final boolean isLast) {
82 }
83
84 /** The only instance. */
85 private static final DummyStepHandler instance = new DummyStepHandler();
86
87 }