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.linear.MatrixVisitorException;
021    
022    /**
023     * Default implementation of the {@link RealMatrixChangingVisitor} 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     * @version $Revision: 1073158 $ $Date: 2011-02-21 22:46:52 +0100 (lun. 21 f??vr. 2011) $
030     * @since 2.0
031     */
032    public class DefaultRealMatrixChangingVisitor implements RealMatrixChangingVisitor {
033    
034        /** {@inheritDoc} */
035        public void start(int rows, int columns,
036                          int startRow, int endRow, int startColumn, int endColumn) {
037        }
038    
039        /** {@inheritDoc} */
040        public double visit(int row, int column, double value) throws MatrixVisitorException {
041            return value;
042        }
043    
044        /** {@inheritDoc} */
045        public double end() {
046            return 0;
047        }
048    
049    }