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.linear;
019
020 import org.apache.commons.math.FieldElement;
021 import org.apache.commons.math.linear.MatrixVisitorException;
022
023 /**
024 * Default implementation of the {@link FieldMatrixChangingVisitor} interface.
025 * <p>
026 * This class is a convenience to create custom visitors without defining all
027 * methods. This class provides default implementations that do nothing.
028 * </p>
029 *
030 * @param <T> the type of the field elements
031 * @version $Revision: 1073158 $ $Date: 2011-02-21 22:46:52 +0100 (lun. 21 f??vr. 2011) $
032 * @since 2.0
033 */
034 public class DefaultFieldMatrixChangingVisitor<T extends FieldElement<T>>
035 implements FieldMatrixChangingVisitor<T> {
036
037 /** Zero element of the field. */
038 private final T zero;
039
040 /** Build a new instance.
041 * @param zero additive identity of the field
042 */
043 public DefaultFieldMatrixChangingVisitor(final T zero) {
044 this.zero = zero;
045 }
046
047 /** {@inheritDoc} */
048 public void start(int rows, int columns,
049 int startRow, int endRow, int startColumn, int endColumn) {
050 }
051
052 /** {@inheritDoc} */
053 public T visit(int row, int column, T value) throws MatrixVisitorException {
054 return value;
055 }
056
057 /** {@inheritDoc} */
058 public T end() {
059 return zero;
060 }
061
062 }