001 /*
002 * Copyright (c) 2005 Einar Pehrson <einar@pehrson.nu>.
003 *
004 * This file is part of
005 * CleanSheets - a spreadsheet application for the Java platform.
006 *
007 * CleanSheets is free software; you can redistribute it and/or modify
008 * it under the terms of the GNU General Public License as published by
009 * the Free Software Foundation; either version 2 of the License, or
010 * (at your option) any later version.
011 *
012 * CleanSheets is distributed in the hope that it will be useful,
013 * but WITHOUT ANY WARRANTY; without even the implied warranty of
014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
015 * GNU General Public License for more details.
016 *
017 * You should have received a copy of the GNU General Public License
018 * along with CleanSheets; if not, write to the Free Software
019 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
020 */
021 package csheets.core.formula.util;
022
023 import csheets.core.Address;
024 import csheets.core.formula.Expression;
025 import csheets.core.formula.Reference;
026 import csheets.core.formula.lang.CellReference;
027
028 /**
029 * An expression visitor that transposes the references in an expression.
030 * The visitor is used for copying and moving formulas between cells.
031 * @author Einar Pehrson
032 */
033 public class ReferenceTransposer extends ExpressionBuilder {
034
035 /** The number of columns to transpose the formula */
036 private int columns;
037
038 /** The number of rows to transpose the formula */
039 private int rows;
040
041 /**
042 * Creates a new reference fetcher.
043 * @param columns the number of columns to transpose formulae
044 * @param rows the number of rows to transpose formulae
045 */
046 public ReferenceTransposer(int columns, int rows) {
047 this.columns = columns;
048 this.rows = rows;
049 }
050
051 /**
052 * Returns a transposed copy of the given expression.
053 * @param expression the expression to rebuild
054 * @return the transposed expression
055 */
056 public Expression getExpression(Expression expression) {
057 return (Expression)expression.accept(this);
058 }
059
060 /**
061 * Transposes the reference.
062 * @param reference the reference to visit
063 */
064 public Expression visitReference(Reference reference) {
065 if (reference instanceof CellReference) {
066 // Fetches reference and address
067 CellReference cellRef = (CellReference)reference;
068 Address address = cellRef.getCell().getAddress();
069
070 // Transposes column index
071 int newColumn = address.getColumn();
072 if (!cellRef.isColumnAbsolute())
073 newColumn += columns;
074
075 // Transposes row index
076 int newRow = address.getRow();
077 if (!cellRef.isRowAbsolute())
078 newRow += rows;
079
080 // Returns new reference
081 return new CellReference(
082 cellRef.getCell().getSpreadsheet().getCell(
083 new Address(newColumn, newRow)),
084 cellRef.isColumnAbsolute(),
085 cellRef.isRowAbsolute()
086 );
087 } else
088 return super.visitReference(reference);
089 }
090 }