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.formula.BinaryOperation;
024 import csheets.core.formula.FunctionCall;
025 import csheets.core.formula.Literal;
026 import csheets.core.formula.Reference;
027 import csheets.core.formula.UnaryOperation;
028
029 /**
030 * A class for printing expressions on multiple lines with indentation.
031 * @author Einar Pehrson
032 */
033 public class ExpressionTreePrinter extends AbstractExpressionVisitor {
034
035 /** The number of spaces to use for each indentation unit */
036 public static final int INDENT_DISTANCE = 3;
037
038 /** The current indentation count */
039 private int indentCount = 0;
040
041 /**
042 * Creates a new expression printer.
043 */
044 public ExpressionTreePrinter() {}
045
046 public Object visitLiteral(Literal literal) {
047 print(literal);
048 return literal;
049 }
050
051 public Object visitUnaryOperation(UnaryOperation operation) {
052 print(operation.getOperator());
053 indentCount++;
054 super.visitUnaryOperation(operation);
055 indentCount--;
056 return operation;
057 }
058
059 public Object visitBinaryOperation(BinaryOperation operation) {
060 print(operation.getOperator());
061 indentCount++;
062 super.visitBinaryOperation(operation);
063 indentCount--;
064 return operation;
065 }
066
067 public Object visitReference(Reference reference) {
068 print(reference);
069 return reference;
070 }
071
072 public Object visitFunctionCall(FunctionCall call) {
073 print(call.getFunction());
074 indentCount++;
075 super.visitFunctionCall(call);
076 indentCount--;
077 return call;
078 }
079
080 private void print(Object o) {
081 String indentation = "";
082 for (int i = 0; i < indentCount * INDENT_DISTANCE; i++)
083 indentation += " ";
084 System.out.println(indentation + o);
085 }
086 }