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.math4.legacy.linear;
19
20 import org.apache.commons.math4.legacy.core.FieldElement;
21
22 /**
23 * Default implementation of the {@link FieldMatrixChangingVisitor} interface.
24 * <p>
25 * This class is a convenience to create custom visitors without defining all
26 * methods. This class provides default implementations that do nothing.
27 * </p>
28 *
29 * @param <T> the type of the field elements
30 * @since 2.0
31 */
32 public class DefaultFieldMatrixChangingVisitor<T extends FieldElement<T>>
33 implements FieldMatrixChangingVisitor<T> {
34 /** Zero element of the field. */
35 private final T zero;
36
37 /** Build a new instance.
38 * @param zero additive identity of the field
39 */
40 public DefaultFieldMatrixChangingVisitor(final T zero) {
41 this.zero = zero;
42 }
43
44 /** {@inheritDoc} */
45 @Override
46 public void start(int rows, int columns,
47 int startRow, int endRow, int startColumn, int endColumn) {
48 }
49
50 /** {@inheritDoc} */
51 @Override
52 public T visit(int row, int column, T value) {
53 return value;
54 }
55
56 /** {@inheritDoc} */
57 @Override
58 public T end() {
59 return zero;
60 }
61 }