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; 021 022 /** 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 $Revision: 811685 $ $Date: 2009-09-05 13:36:48 -0400 (Sat, 05 Sep 2009) $ 031 * @since 2.0 032 */ 033 public class DefaultFieldMatrixChangingVisitor<T extends FieldElement<T>> 034 implements FieldMatrixChangingVisitor<T> { 035 036 /** Zero element of the field. */ 037 private final T zero; 038 039 /** Build a new instance. 040 * @param zero additive identity of the field 041 */ 042 public DefaultFieldMatrixChangingVisitor(final T zero) { 043 this.zero = zero; 044 } 045 046 /** {@inheritDoc} */ 047 public void start(int rows, int columns, 048 int startRow, int endRow, int startColumn, int endColumn) { 049 } 050 051 /** {@inheritDoc} */ 052 public T visit(int row, int column, T value) 053 throws MatrixVisitorException { 054 return value; 055 } 056 057 /** {@inheritDoc} */ 058 public T end() { 059 return zero; 060 } 061 062 }