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 * Interface defining a visitor for matrix entries. 022 * 023 * @see DefaultRealMatrixPreservingVisitor 024 * @version $Revision: 778191 $ $Date: 2009-05-24 12:44:52 -0400 (Sun, 24 May 2009) $ 025 * @since 2.0 026 */ 027 public interface RealMatrixPreservingVisitor { 028 029 /** 030 * Start visiting a matrix. 031 * <p>This method is called once before any entry of the matrix is visited.</p> 032 * @param rows number of rows of the matrix 033 * @param columns number of columns of the matrix 034 * @param startRow Initial row index 035 * @param endRow Final row index (inclusive) 036 * @param startColumn Initial column index 037 * @param endColumn Final column index (inclusive) 038 */ 039 void start(int rows, int columns, 040 int startRow, int endRow, int startColumn, int endColumn); 041 042 /** 043 * Visit one matrix entry. 044 * @param row row index of the entry 045 * @param column column index of the entry 046 * @param value current value of the entry 047 * @throws MatrixVisitorException if something wrong occurs 048 */ 049 void visit(int row, int column, double value) 050 throws MatrixVisitorException; 051 052 /** 053 * End visiting a matrix. 054 * <p>This method is called once after all entries of the matrix have been visited.</p> 055 * @return the value that the <code>walkInXxxOrder</code> must return 056 */ 057 double end(); 058 059 }