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    /**
021     * Default implementation of the {@link RealMatrixChangingVisitor} interface.
022     * <p>
023     * This class is a convenience to create custom visitors without defining all
024     * methods. This class provides default implementations that do nothing.
025     * </p>
026     * 
027     * @version $Revision: 778191 $ $Date: 2009-05-24 12:44:52 -0400 (Sun, 24 May 2009) $
028     * @since 2.0
029     */
030    public class DefaultRealMatrixChangingVisitor implements RealMatrixChangingVisitor {
031    
032        /** {@inheritDoc} */
033        public void start(int rows, int columns,
034                          int startRow, int endRow, int startColumn, int endColumn) {
035        }
036    
037        /** {@inheritDoc} */
038        public double visit(int row, int column, double value)
039            throws MatrixVisitorException {
040            return value;
041        }
042    
043        /** {@inheritDoc} */
044        public double end() {
045            return 0;
046        }
047    
048    }