    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     * Interface defining a visitor for matrix entries.
    025     *
    026     * @param <T> the type of the field elements
    027     * @version $Revision: 1073158 $ $Date: 2011-02-21 22:46:52 +0100 (lun. 21 f??vr. 2011) $
    028     * @since 2.0
    029     */
    030    public interface FieldMatrixChangingVisitor<T extends FieldElement<?>> {
    031
    032        /**
    033         * Start visiting a matrix.
    034         * <p>This method is called once before any entry of the matrix is visited.</p>
    035         * @param rows number of rows of the matrix
    036         * @param columns number of columns of the matrix
    037         * @param startRow Initial row index
    038         * @param endRow Final row index (inclusive)
    039         * @param startColumn Initial column index
    040         * @param endColumn Final column index (inclusive)
    041         */
    042        void start(int rows, int columns,
    043                   int startRow, int endRow, int startColumn, int endColumn);
    044
    045        /**
    046         * Visit one matrix entry.
    047         * @param row row index of the entry
    048         * @param column column index of the entry
    049         * @param value current value of the entry
    050         * @return the new value to be set for the entry
    051         * @throws MatrixVisitorException if something wrong occurs
    052         */
    053        T visit(int row, int column, T value)
    054            throws MatrixVisitorException;
    055
    056        /**
    057         * End visiting a matrix.
    058         * <p>This method is called once after all entries of the matrix have been visited.</p>
    059         * @return the value that the <code>walkInXxxOrder</code> must return
    060         */
    061        T end();
    062
    063    }