001 /** 002 * ========================================= 003 * LibFormula : a free Java formula library 004 * ========================================= 005 * 006 * Project Info: http://reporting.pentaho.org/libformula/ 007 * 008 * (C) Copyright 2006-2007, by Pentaho Corporation and Contributors. 009 * 010 * This library is free software; you can redistribute it and/or modify it under the terms 011 * of the GNU Lesser General Public License as published by the Free Software Foundation; 012 * either version 2.1 of the License, or (at your option) any later version. 013 * 014 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 015 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 016 * See the GNU Lesser General Public License for more details. 017 * 018 * You should have received a copy of the GNU Lesser General Public License along with this 019 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, 020 * Boston, MA 02111-1307, USA. 021 * 022 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 023 * in the United States and other countries.] 024 * 025 * 026 * ------------ 027 * $Id: SubtractOperator.java 2752 2007-04-10 14:10:41Z taqua $ 028 * ------------ 029 * (C) Copyright 2006-2007, by Pentaho Corporation. 030 */ 031 package org.jfree.formula.operators; 032 033 import java.math.BigDecimal; 034 035 import org.jfree.formula.EvaluationException; 036 037 /** 038 * Creation-Date: 31.10.2006, 16:34:11 039 * 040 * @author Thomas Morgner 041 */ 042 public class SubtractOperator extends AbstractNumericOperator 043 { 044 public SubtractOperator() 045 { 046 } 047 048 protected Number evaluate(final Number number1, final Number number2) throws EvaluationException 049 { 050 if ((number1 instanceof Integer || number1 instanceof Short) && 051 (number2 instanceof Integer || number2 instanceof Short)) 052 { 053 return new BigDecimal (number1.longValue() - number2.longValue()); 054 } 055 056 final BigDecimal bd1 = new BigDecimal(number1.toString()); 057 final BigDecimal bd2 = new BigDecimal(number2.toString()); 058 return bd1.subtract(bd2); 059 } 060 061 public int getLevel() 062 { 063 return 200; 064 } 065 066 public String toString() 067 { 068 return "-"; 069 } 070 071 public boolean isLeftOperation() 072 { 073 return true; 074 } 075 076 /** 077 * Defines, whether the operation is associative. For associative operations, 078 * the evaluation order does not matter, if the operation appears more than 079 * once in an expression, and therefore we can optimize them a lot better than 080 * non-associative operations (ie. merge constant parts and precompute them 081 * once). 082 * 083 * @return true, if the operation is associative, false otherwise 084 */ 085 public boolean isAssociative() 086 { 087 return false; 088 } 089 090 }