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 }