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.math3.linear;
019
020 import org.apache.commons.math3.FieldElement;
021
022 /**
023 * Default implementation of the {@link FieldMatrixChangingVisitor} interface.
024 * <p>
025 * This class is a convenience to create custom visitors without defining all
026 * methods. This class provides default implementations that do nothing.
027 * </p>
028 *
029 * @param <T> the type of the field elements
030 * @version $Id: DefaultFieldMatrixChangingVisitor.java 1416643 2012-12-03 19:37:14Z tn $
031 * @since 2.0
032 */
033 public class DefaultFieldMatrixChangingVisitor<T extends FieldElement<T>>
034 implements FieldMatrixChangingVisitor<T> {
035 /** Zero element of the field. */
036 private final T zero;
037
038 /** Build a new instance.
039 * @param zero additive identity of the field
040 */
041 public DefaultFieldMatrixChangingVisitor(final T zero) {
042 this.zero = zero;
043 }
044
045 /** {@inheritDoc} */
046 public void start(int rows, int columns,
047 int startRow, int endRow, int startColumn, int endColumn) {
048 }
049
050 /** {@inheritDoc} */
051 public T visit(int row, int column, T value) {
052 return value;
053 }
054
055 /** {@inheritDoc} */
056 public T end() {
057 return zero;
058 }
059 }