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
18package org.apache.commons.math.linear;
19
20import org.apache.commons.math.FieldElement;
21import org.apache.commons.math.linear.MatrixVisitorException;
22
23/**
24 * Default implementation of the {@link FieldMatrixChangingVisitor} interface.
25 * <p>
26 * This class is a convenience to create custom visitors without defining all
27 * methods. This class provides default implementations that do nothing.
28 * </p>
29 *
30 * @param <T> the type of the field elements
31 * @version $Revision: 1073158 $ $Date: 2011-02-21 22:46:52 +0100 (lun. 21 févr. 2011) $
32 * @since 2.0
33 */
34public class DefaultFieldMatrixChangingVisitor<T extends FieldElement<T>>
35    implements FieldMatrixChangingVisitor<T> {
36
37    /** Zero element of the field. */
38    private final T zero;
39
40    /** Build a new instance.
41     * @param zero additive identity of the field
42     */
43    public DefaultFieldMatrixChangingVisitor(final T zero) {
44        this.zero = zero;
45    }
46
47    /** {@inheritDoc} */
48    public void start(int rows, int columns,
49                      int startRow, int endRow, int startColumn, int endColumn) {
50    }
51
52    /** {@inheritDoc} */
53    public T visit(int row, int column, T value) throws MatrixVisitorException {
54        return value;
55    }
56
57    /** {@inheritDoc} */
58    public T end() {
59        return zero;
60    }
61
62}
63