1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.math.linear;
19
20 import org.apache.commons.math.FieldElement;
21
22 /**
23 * Interface defining a visitor for matrix entries.
24 *
25 * @param <T> the type of the field elements
26 * @version $Revision: 778191 $ $Date: 2009-05-24 12:44:52 -0400 (Sun, 24 May 2009) $
27 * @since 2.0
28 */
29 public interface FieldMatrixChangingVisitor<T extends FieldElement<?>> {
30
31 /**
32 * Start visiting a matrix.
33 * <p>This method is called once before any entry of the matrix is visited.</p>
34 * @param rows number of rows of the matrix
35 * @param columns number of columns of the matrix
36 * @param startRow Initial row index
37 * @param endRow Final row index (inclusive)
38 * @param startColumn Initial column index
39 * @param endColumn Final column index (inclusive)
40 */
41 void start(int rows, int columns,
42 int startRow, int endRow, int startColumn, int endColumn);
43
44 /**
45 * Visit one matrix entry.
46 * @param row row index of the entry
47 * @param column column index of the entry
48 * @param value current value of the entry
49 * @return the new value to be set for the entry
50 * @throws MatrixVisitorException if something wrong occurs
51 */
52 T visit(int row, int column, T value)
53 throws MatrixVisitorException;
54
55 /**
56 * End visiting a matrix.
57 * <p>This method is called once after all entries of the matrix have been visited.</p>
58 * @return the value that the <code>walkInXxxOrder</code> must return
59 */
60 T end();
61
62 }